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  1. This page ( does not render properly, either in Firefox or Safari, on a mac running OS 10.3.9. The “B” graph is about 1/2 covered by the brown list on the right side of the page. I could test from a windows machine, but I’ll bet some of the readers of this site are running macs!

    [Response:thanks! fixed now. David]

    Comment by John Palkovic — 27 May 2006 @ 10:24 AM

  2. Is there any hope for gaining insight into the interaction between a “carbon spike transient” and the kinds of feedbacks these slower processes bring by examining the PETM event?

    [Response: The timing is father fuzzy from this event. There may be an initial 13-c change in planktonic forams (surface ocean) before the benthic ones (deep ocean), but it’s impossible to tell if the invasion took 100 years or 500, which is the information that would relevant to this question. ]

    Re Torn et al. It seems problematic to draw too many parallels between a process that took 10K yrs and one that is playing out over one century, especially if it involves the biosphere which will undoubtably react very differently to such a sudden warming. And what about the multi-century lag between T and CO2 in deglaciation? Why do they expect to see effects in this century?

    Do either paper’s conclusions depend on specific mechanisms or is it more based on observation of past correlations?

    [Response:Not really. I think they’d be stronger if the mechanisms were well-known and quantifiable, more than they are. David]

    Comment by Coby — 27 May 2006 @ 11:00 AM

  3. Why didn’t this huge CO2 feedback not occur in the Eemian?

    [Response:Warmer temperature, but not higher CO2? Good question. David]

    I can only see a response of 10 ppm/K.

    Comment by Hans Erren — 27 May 2006 @ 11:27 AM

  4. You are all missing the point. Water vapour is the main greenhouse gas not carbon dioxide. When the Artic ice melts (due to the increase CO2 levels)then the increase in water vapour due to a warmer and wetter ocean surface will have a runaway effect caused by the positive feedback from the saturated vapour pressure which increases exponetially. This will be compounded by the loss of albedo from the sea ice. The time to press the big red Stop button has long passed.

    It is well known that carbon dioxide did not drive the recent deglaciation, nor did it (or methane) drive the rapid warming at the end of the Younger Dryas. It is not the main player in the climate stakes, but by moving the snow line it can alter the planetary albedo and so trigger a rapid warming.

    [Response: This isn’t a correct statement. The amplifying effect of water vapor feedback is already incorporated in the “radiative” temperature vs. CO2 curves in Figs (a) and (b). The detailed shape of those curves is affected by the specific assumptions made about water vapor feedback (specifically the way in which relative humidity in the mid to upper troposphere changes with temperature). –raypierre]

    Comment by Alastair McDonald — 27 May 2006 @ 11:38 AM

  5. As I read the article, the positive feed back, is either a potosynthesis or respiration.

    This paper, using carbon isotope measurements concludes a net transfer to land of some 600 Gt: Estimate of deglaciation carbon transfer

    Woods Hole puts the amount of upper ocean carbon (first 100 meters?) at less than 800 gigatons while land holds a little less than 2,000 gigatons, and deep ocean has someting like 40,000 gigaton. Prior to fossil fuel use the atmosphere held something less than 600 gigaton. I hope my conversion from petagram to gigaton is correct.

    So, the mind boggles with the various scenarios. It seems that the land response to deglaciation is more complex then a simple scenario favoring respiration early and photosynthesis later, which was my guess. The tropics have less carbon and nothern tundra is suspected to be a net carbon source as it warms, yet the northern tundra gained carbon during deglaciation.

    [Response:You are correct that the 13-C seems to tell us that there was net uptake of organic carbon during the deglaciation, which makes explaining the atmospheric CO2 rise more difficult to explain. Truly the mind boggles. David]

    Given the length of the Holocene, the land carbon, worldwide, must have reached eqilibrium, all things being equal. If I compare inter-glacial time periods and holocene plant growth rates of the northern hemispere I suspect that the net introduction of nothern carbon continued well into the holocene. A simple transfer of tropical carbon north does not explain the additional 600gt total, unless the paper cited is wrong; or the net transfer occured early during deglaciation.

    The deep oceans might have been net producer of carbon until the introduction of fossil carbon and deep upwelling stopped as the fossil carbon atmospheric pressure grew.

    Is there something in the science of ocean carbon that could cause increasing ocean carbon on the surface to push back on the release of deep carbon, a change in circulation, or am I just wrong about upwelling of deep carbon?

    [Response:CO2 invades the ocean in some places, where it’s cold or where CO2 has been stripped out by phytoplankton, and it invades in other places. I don’t think of the deep sea as being a huge source of carbon waiting to get out, I think of it as being in equilibrium with the atmosphere. Of course, if you stirred up the ocean more quickly than biology could keep up, or if you killed the biology, then the deep sea would be a source of carbon to the air. David]

    Comment by Matt — 27 May 2006 @ 11:45 AM

  6. First of all, when do we start heading for that alleged “equilibrium” CO2 level?” We’re doing a dynamic process here, not a static one, and the warming we get will come from the CO2 we have, not the amount we ought to eventually expect with the current temperature. That leftward arrow is a fiction until people get alarmed in a constructive way, which is not yet a general reaction. For now, diagram A is our actual condition, and we need a serious change in behavior to make B apply (which may not occur until a shortage of fuel-burning humans sets in.)

    [Response:Situation B is where we are, insofar as the CO2 is still invading the oceans and the land. You are right that the equilibration arrow is a fiction because we’re adding CO2 faster than it goes away. If we cut emission by about half, uptake would balance release and atmospheric CO2 would stabilize. David ]

    The immediate effect of these positive feedback processes is not simply an increase in the eventual equilibrium temperature, but an increase in the amount of CO2 entering the atmosphere and increasing the current temperature. Perhaps not a large enough increase to dominate our own contributions, but working to bring us closer to whatever other potentially destabilizing thresholds may lie ahead.

    Comment by Forrest Curo — 27 May 2006 @ 11:52 AM

  7. Re #2 The question about the 10ka+ spikes of Carbon dioxide is whether it is cause or effect of something. We have several things to take into account. First, the CO2 contents of the oceans is double digits compared to the atmosphere; next, atmospheric pCO2 is very sensitive to changes in surface curents (eg El Nino), changing sink areas and CO2 venting areas and there is clear evidence for oceanic CO2 exchange . Furthermore, the Thermohaline ocean current underwent strong and quick changes around the end of the ice age (Younger Dryas).

    Therefore, it cannot be excluded that those CO2 spikes were the direct and exclusive result of those oceanic changes (Hodell et al 2001), rather than that it was primarily temperature cause – effect related.

    Moreover, the initial warming is assumed to have started about 19ka ago (Clark et al 2004), whereas the start of the CO2 spike is dated not before 17ka (Monnin et al 2004). Hence maintaining the claim of interaction between the two appears to require some revisiting of the evidence.


    Clark et al (2004), Rapid Rise of Sea Level 19,000 Years Ago and Its Global Implications. Science 21 May 2004: 1141-1144

    Hodell D.A et al (2001) Late Pleistocene evolution of the ocean’s carbonate system, Earth and Planetary Science Letters 192 (2001) 109-124

    Monnin, E., et al 2004. EPICA Dome C Ice Core High Resolution Holocene and Transition CO2 Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2004-055.

    Comment by Andre — 27 May 2006 @ 1:32 PM

  8. Does that big red button happen to say ‘Do Not Press This Button’?

    Comment by Thomas Lee Elifritz — 27 May 2006 @ 2:11 PM

  9. Question: Lakes with CO2 at the bottom sometimes turn over and the CO2 kills a whole village. Can the ocean do that too, killing the whole planet? How high above sea level do I have to live to be safe from ocean CO2 overturn?

    [Response: You’re thinking of Lake Nyos, I imagine. The uptake of atmospheric CO2 at the ocean surface could not conceivably create the kind of CO2 profile that lead to the lake-type catastrophic release; CO2 enters through the surface of the ocean, and only gradually is brought to the deep ocean. One of the proposed schemes for CO2 sequestration, however, is to inject liquified CO2 directly to the bottom of the ocean, and here it’s not as immediately obvious that a catastrophic release can be ruled out. This was discussed in the IPCC carbon sequestration report that just came out, and a Lake Nyos type catastrophic release seems to be essentially impossible, because of the greater depths and pressures involved in the ocean, and the greater stratification that is working to inhibit vertical mixing. The ecological effects of ocean floor CO2 disposal provide lots of cause for worry, but catastrophic release is one thing you can probably breathe easy about. –raypierre]

    Comment by Edward Greisch — 27 May 2006 @ 2:18 PM

  10. I was thinking along the lines of comment 6. To continue with the thought it seems to me that identified positive feedbacks to increase the effect of higher CO2 levels operate in the near term. Examples include: albedo change from north pole sea ice melt and northern forest albedo decrease. Other identified positive feedback loops include methane release from warming permafrost and decreased CO2 absorption by warmer seas that also act in the near term. Other positive loops that accelerate glacial flow rates and melt, affect sea level.

    Corrective negative feedbacks to sequester CO2 operate in the longer term.

    It seems we have initiated a global system shift to a different state. To reverse this shift wouldn’t we have to reduce the amount of CO2 in the atmosphere? This implies reducing CO2 emissions to less than the rate of sequestration, not just slowing the rate of increase in emissions. Since current trends are for CO2 emissions to continue to increase is there in fact any real prospect avoiding rapid global warming?

    Comment by Don Condliffe — 27 May 2006 @ 2:34 PM

  11. How long would that extra 25% of our emissions remain in the atmosphere if we were to stop emitting CO2 today? Tens of thousands of years? Hundreds of thousands of years?

    [Response:Some of it (10% or so) for hundreds of thousands of years. This was the topic of my first post at realclimate! David]

    Comment by teacher ocean — 27 May 2006 @ 4:12 PM

  12. The article makes sense to me, as far as the last deglaciation is concerned. However I have a problem with the LIA. If Scheffer et al were able to identify a feedback response, does this imply that the LIA was a global event (or at least more widespread than the IPCC thought it was)?

    [Response: Experiments using coupled climate-carbon cycle models such as Gerber et al (2003) [Gerber, S., Joos, F., Bruegger, P.P., Stocker, T.F., Mann, M.E., Sitch, S., Constraining Temperature Variations over the last Millennium by Comparing Simulated and Observed Atmospheric CO2, Climate Dynamics, 20, 281-299, 2003] suggest that the hemispheric-mean cooling of the LIA indicated by the reconstructions featured in the IPCC TAR are consistent with pre-industrial CO2 variations, and that significant greater hemispheric-mean temperature variations would actually be inconsistent the CO2 record of the past millennium. –mike]

    If there was a feedback within a 100 year period, I guess that it could have been caused by cooling prior to this (the LIA started, I believe, one or two centuries before the period studied). I take your point about a CO2 spike in current times, but do their results imply that the feedbacks respond faster during a cooling period than during a warming period?

    Comment by Stewart Argo — 27 May 2006 @ 5:28 PM

  13. It seems to me there’s a curious quirk of a result like this though, that it actually REDUCES climate sensitivity, as measured by temperature change associated with a given CO2 increase – because the positive feedback is to increase the CO2 for a given temperature.

    That’s doesn’t mean it makes things better – it makes things worse because anthropogenic CO2 is enhanced by naturally released CO2 from the positive feedback. But it’s perhaps a limitation of just looking at a doubling of CO2 in describing the results of climate models.

    [Response:No it doesn’t – because classical ‘climate sensitivity’ is only defined for constant CO2 so these feedbacks just don’t come into it. The confusion between the articifical construct ‘climate sensitivity’ and the real question of how climate is sensitive to increasing emissions is very common though. – gavin]

    Comment by Arthur Smith — 27 May 2006 @ 6:42 PM

  14. Over the whole 420,000 years of Vostok data, the linear regression between CO2 levels (lagging with many hundreds to many thousands of years) and temperature (derived from dD), was some 8.1 ppmv/K.

    Taking the 1.5-4.5 K warming of the IPCC range of model projections, this would lead to an extra 12-36 ppmv of CO2 in full equilibrium (after thousands of years…), due to warmer ocean temperatures. Or some 4-13% extra over the 280 ppmv induced by humans to reach a CO2 doubling. Or some 1.56-5.1 K warming (which is lower than the 1.6-6.0 K derived from the model by Sheffer ea.) instead of the original 1.5-4.5 K projection.

    Further I wonder how Sheffer ea. could derive anything from the miniscule changes in CO2 levels in one century of the LIA. The variation in temperature over the past millennium was between 0.2 K (MBH98/99) and 1.0 K (Huang, bore holes), which means a CO2 variation of 1.6-8 ppmv. The effect of this on temperature is unmeasurable… (BTW, the variation in CO2 between MWP and LIA was near 9 ppmv in the Taylor Dome ice core).

    [Response: The numbers you cite for “the variation in temperature over the past millennium” are nonsensical (the range of total variation only differs by about 0.4C for the full range of reconstructions, such as shown in this previous post). For actual quantitative comparisons between observed pre-industrial CO2 variations and what is expected given estimated temperature variations and their uncertainties, see the Gerber et al (2003) paper cited above. The comparisons are consistent with 2xCO2 sensitivities within the conventionally cited range of 1.5 to 4.5, but not much higher. –mike]

    If we will need a panic button or not, depends of what the real effect of a CO2 doubling will be, but the CO2 feedback seems of less importance here…

    [Response: Another mistake you seem to be making is that you’re regressing glacial-interglacial CO2 against Vostok temperature, which is a measure of the Antarctic temperature changes. Then you’re applying that coefficient to the global mean temperature. It’s a fallacy to take the Antarctic temperature swings as representative of the magnitude of the global mean, or even of the Southern Hemisphere mean. –raypierre]

    Comment by Ferdinand Engelbeen — 27 May 2006 @ 7:26 PM

  15. Re 14

    The amount of knowledge and evidence already justifies pushing the red button, and has justified pushing it for some time. This weekend, ND and MN has daily max temps in the 90s and humidity, but trees have yet to completely leaf out. Earlier this month, TV meteorologists sounded out below normal May temps … but not anymore. Monthly average temperatures in the Upper Midwest have near or above the historical averages at climate stations since 2001. Nobody wants to get accused of pushing panic buttons and feel a loss of credibility. Too bad it seems to be that way, otherwise we may have acted years ago to reduce emissions.

    [Response:Hang on, my rhetorical fluorish of the “Stop the Press” button at IPCC seems to have confused several people (this post, #14, and #8). I meant to say, should the IPCC, which is soon going to start printing its next Climate Scientific Assessment report, stop the press, to revise its estimate of the climate sensitivity or future warming. I did not mean to imply that we should not be concerned about CO2 emissions (the button being whether to take climate change seriously or not). My apologies for all the confusion. David]

    Comment by pat neuman — 27 May 2006 @ 9:29 PM

  16. To the Note 6: “If we cut emission by about half, uptake would balance release and atmospheric CO2 would stabilize. David”
    certainly, this would hold true, if the uptake capacity of atmosphere and for CO2 was constant in the future. But taking in mind increased cumulative CO2 rise (or is this increased rise in CO2 due to increased emissions, not due to decreasing absorbing capacity of ecosystems?) and continuing increasing temperature, the amount of “equilibrium carbon stop” needed will be higher from year to year, or?

    [Response:Yeah, you’re right. Cutting emissions enough to balance natural uptake today would only stabilize CO2 until the ocean and land uptake saturates, at which point CO2 would start to rise unless emission were cut further. David. ]

    Comment by Alexander — 28 May 2006 @ 5:16 AM

  17. David, re your response about which big Red button should be pressed, it was I who proposed that it should be the Really Big one in #4. There was no need for you to apologise for my corruption of your message :-)

    As Ray pointed out in his reply to Ferdi, the correlation between temperature and CO2 in the Vostock core is irrelevant to climate in the northern hemisphere where virtually all the people of the world live. The real danger from positive feedback is a repeat of the end of the Younger Dryas when Greenland temperatures jumped by 10C in three years and by 20C in thirty years [Alley, R. “The Two Mile Time Machine”, 2000.] That would have led to temperature changes in the bread baskets of the world which would not have been so severe, but the effect to the water cycle stretched as far south as the Amazon Basin [Maslin, M.A., and S.J. Burns, “Reconstruction of the Amazon Basin effective moisture availability over the last 14,000 years” Science, 290, 2285-2287 (2000)]. There is no evidence that positive feedback from CO2 or methane was the driving force for that event.

    Ray argues that the models are already including the effects of water vapour, but I am arguing that they are not doing it correctly. The models cannot reproduce the amount of cooling during the Younger Dryas, and that can only be because the water vapour sensitivity is wrong. In fact, we know that is true from “Anthropogenic greenhouse forcing and strong water vapor feedback increase temperature in Europe” by Rolf Philipona et al. GRL, 2005. Ray’s greenhouse effect of water vapour in the upper troposphere is irrelevant, because the atmosphere is in a state of LTE there! And we know from the MSU and radiosonde measurements that the upper troposphere is hardly warming, and what warming is happening is probably due to the Asian Brown Cloud.

    [Response: What you said I pointed out was not in fact what I pointed out. CO2 is global, and your remarks about regional influence are completely unrelated to my point, which was simply that Antarctic deuterium temperature fluctuations are not the same as global mean temperature fluctuations, which (in the ice age problem) are not even themselves necessarily the temperature that feeds back on CO2. Therefore Engebeen’s correlation likely underestimates the feedback, insofar as one can estimate it at all from data of this sort. The comments in your last paragraph are so completely wrong, and in a way we’ve gone over so many times before, that I won’t bother responding again. –raypierre]

    Comment by Alastair McDonald — 28 May 2006 @ 6:54 AM

  18. Re #17


    “The real danger from positive feedback is a repeat of the end of the Younger Dryas when Greenland temperatures jumped by 10C in three years and by 20C in thirty years [Alley, R. “The Two Mile Time Machine”, 2000.]”

    This is the interpretation of Alley of isotope variation, it could be something different. But Antarctic isotopes are not representative for global temperature why would Greenland summit isotope-temperatures be representative of NH temperatures? It is not even true for South Greenland:

    Comment by Andre — 28 May 2006 @ 10:39 AM

  19. Re 15
    It might have been warmer in the midwest but most of Europe was cooler than average in May.I suppose neither of these facts will bear any relationship to the global temperature after all they are just local events.

    [Response:All of these local effects go into the statistics, so they do influence the mean. But if there are more warm anomalies than cold, the global anomaly will be warm. That’s what averaging means. -gavin]

    Comment by Bryn Hughes — 28 May 2006 @ 11:03 AM

  20. I know some global warming deniers who have jumped from “global warming isn’t happening” to “global warming is not human caused” to the latest “it is too late to do anything about it.” The old version of this was simply that global warming is an on/off switch – once any global warming happens, well degree does not matter and that is it, let’s move on. But that I think has proven too obviously wrong – I mean the answer is pretty self-evident; it is like saying there is no difference between a mild sunburn, and catching on fire.

    However I’m seeing feedback seized on as the next version of the ‘too late’ trope. “We have all that methane under the permafrost in siberia, and the hydrates under the iceaps. Feedback has already reached the point where they are all going to be released; this will dwarf human emissions, so there is no point in doing anything about those human emissions.” Early days on this one , but I’m betting you’ll be hearing more about it. The intersting thing about it is it may provide additional evidence of how driven by the loonies the denier side is. This trope is not put foward by the few scientists or even much in evidence among the institutes who claim be scientific. It is strickly among the loonies who don’t even make global warming their main focus – for whom global warming denial is just one belief alongside a number of other “interesting” views. But I’m going to make a prediction. Within the next twelve months you are going to hear well known deniers add the “it’s too late; the climate has tipped; the coming of the methane is inevitable” to their standard list. I’m posting it here, both because it is relevent to the subject you are discussing and because I’m making my prediction publicly, so that the accuracy (or otherwise) may be tested. If a talking point that is not put forward currently by any global warming denier with scientific credentials or even any major denier think tank becomes a position advocated either by such think tanks or those with such credentials, I think it will be a tiny piece of additional evidence that such denial is indeed politics driven and not merely a maverick scientific viewpoint.

    Comment by Gar Lipow — 28 May 2006 @ 11:26 AM

  21. re 19. I also said that monthly average temperatures in the Upper Midwest were above historical averages since 2001.

    I could have added that annual temperature averages were above historical averages for the last nine years in a row and that Jan-Apr temperature averages in ND and northern MN clearly show warming trends which are based on 100-110 mean temperature averages at NOAA climate stations. However, I already said all that and I provided my link to the plots many times to RC.

    Strong regional trends over a 100-110 year period is much more significant than than one or a couple days or months of above or below the official recent 30 year National Weather Service averages which are used to define normal for temperatures at climate stations.

    re 20. I think you missed that … bwe know what’s happening but our day to day lives are a struggle enough, and besides, what one person does or doesn’t do is insignificant. Get a life.

    Comment by pat neuman — 28 May 2006 @ 11:58 AM

  22. As a non scientist who took statistics a long time ago I struggle to understand the analysis of all the data that is presented here on this site. Though I suspect I am able to get the general gist of the fact that according to the general consensus we may be in for some significant climate change begining now and progressing into the commimg centuries, the consequences of which we probably cannot fully asses at the present time.

    I suspect that Gar Lipow is not far off the mark with regards as he calls them “Loonies” However what I find much more disturbing is those who are crazy like foxes and have enormous vested interests such as the oil and energy industries. They have both the money and the power to sway the general public opinion and are more than able thus to have their way.

    Case in point an article in today’s New York Times business section:
    talks about what is happening with coal. The discussion seems to focus on the application of cleaner tecnnology to reduce soot emissions and reduce things like acid rain. That certainly may sound like a good idea. Though it seems to me to miss the point entirely. I think that any carbon dioxide emitting energy source regardless of how currently inexpensive it may seem at the moment has to have the cost of the long term societal consequences factored in to the bottom line. In other words if the use of cheap coal will in the long term be a big part of accelerating climate change and if that change can be shown to have deleterious effects on the livelihoods of of societies through drought and famine and floods etc… then they should only be allowed to embark on such business ventures if they are held accountable for the consequences from the get go. As I see it now if these scenarios should come to pass they will suffer no consequences whatsoever. So they feel free to pursue their profits at any cost and since they will appear to be selling cheap energy (the real costs of which will be denied) the ignorant public will be a willing participant in this unfolding global fiasco. ‘CO2: they call it pollution, we call it Life!’ is not in my opinion as funny as it seems at first glance.

    [Response:That’s exactly why some kind of regulatory environment for CO2 is needed, and why the market won’t take care of it all by itself. There are regulations in place (despite attempts to weaken and dismantle them) that control soot, sulfur compounts, nitrogen compounds and (soon) mercury, and therefore companies spend money on the technology to reduce emissions of these. However, there are no market signals that represent the environmental costs of CO2 emissions, so a company would have to be crazy — indeed irresponsible in the fiduciary sense — to spend extra money reducing CO2 emissions, for example by building IGCC plants and providing for sequestration. Right now, burning coal in pulverized coal plants makes great economic sense, and there is no reason in the world it won’t expand — as indeed it is doing. The tragedy is that a coal plant will have a 50-60 year capital life, perhaps more. If a company took the long view and figured in the cost of capturing and sequestering CO2, not only would IGCC plants look cheaper than pulverized coal, but even coal with IGCC would start to look less economically attractive than various alternatives. –raypierre]

    Comment by Fernando Magyar — 28 May 2006 @ 12:26 PM

  23. Re# 16

    Alexander, you said:

    “But taking in mind increased cumulative CO2 rise (or is this increased rise in CO2 due to increased emissions, not due to decreasing absorbing capacity of ecosystems?)”

    I used available data on global 2003-2005 fossil fuel use and its CO2 emissions and the 2006 Jan-APR Mauna Loa CO2 concentration measurements and the following might address your question:

    Using 2006 JAN-MAY 11 hourly CO2 measurements provided by NOAA Earth Systems Research Laboratoryâ??s Carbon Cycle Greenhouse Gases Group, I derived a January increase of 2.98 ppmv CO2 over 2005 January concentration. Please note, my calculations are based upon preliminary data.

    Is that increase attributable to increased fossil fuel use?

    Global fossil fuel use data from BPâ??s Statistical Review of World Energy, June 2005 provided the following coal, oil and natural gas production for 2003 and 2004. I estimated 2005 data using conservative percent increase.

    2003- 5.185 billion tons
    2004- 5.538 billion tons
    2005- 5.954 billion tons (7.5 percent increase)

    2003- 28.1 billion barrels
    2004- 29.3 billion barrels
    2005- 30.8 billion barrels (5 percent increase)

    Natural Gas
    2003- 92,053 billion cu ft.
    2004- 94,462 billion cu ft.
    2005- 97,298 billion cu ft. (3 percent increase)

    Global Tons of CO2

    2004- 12.671 billion tons
    2005- 13.621 billion tons

    2004- 12.851 billion tons
    2006- 13.494 billion tons

    Natural Gas
    2004- 5.526 billion tons
    2005- 5.691 billion tons

    Total CO2
    2004- 31.048 billion tons
    2005- 32.807 billion tons

    1 GtC corresponds to ~3.67 Gt CO2

    2.12 GtC or ~7.8 Gt CO2 correspond to 1 ppmv CO2 in the

    D. Schimel,,CO2 and the carbon cycle. Pages 76-86
    in [IPCC 95])

    The January 2006 Mauna Loa CO2 increase over 2005 was 2.98 ppmv, or 23 billion tons of CO2.

    So, I conclude that the January 2006 increase was equivalent to 74 percent of total 2004 global fossil fuel CO2 emissions.

    CO2 uptake by ocean and terrestrial sinks is not immediate and uptake is affected by temperature.

    The energy and CO2 data are readily available to compare January 2006 increase against any successive Januaries from 1958 to 2005. If you are interested, I can provide more comparisons.

    I hear many different explanations for the dramatic Jan 2006 over 2005 increase. None were based on analysis – just thow out lines such as fires, El Nino (?), very cold winter in Europe and Russia, China and India energy use. The January CO2 increase is not faulted by the measurement process itself. The Keeling team have a rigid, quality-controlled standard of excellence.

    So, any suggestions to add to the “cause” list?

    Comment by John L. McCormick — 28 May 2006 @ 12:51 PM

  24. I think that, in general, processes in which one component lags another and is the effect of that cause or that they share a common cause, the lagging component will display a diminution in response to changes of a shorter period than the period of the lag.

    A response with a millennium lag will look smoothed on a centennial time scale, one with a century lag will look smoothed on a decadal time scale, etc.

    From the little I know of ice core evidence I am left with the impression that the CO2 response lags considerably => 500 years. Such a CO2 response mechanism, if this is a single mechanism, would be unlikely to be able to track sub centennial variations which is what I believe has been shown for the Little Ice Age record.

    Alternatively there could be different mechanisms or even a reversal from effect to cause between these two examples. It is not clear to me that a single mechanism could be responsible for both.

    I do not know how discriminating the ice core records are on decadal scale nor if anyone has looked for a second response with a short lag in these records. Absence of any short term CO2 signal in the presence of short term termperature signals would speak against a CO2 response to temperature with a short time lag, at least during that epoch.

    Regarding the near future; If the lag is very short (< =10 years) , it might not be possible to extract the CO2 response from the CO2 cause prior to it all being a postmortem exercise unless a significant reduction in emissions occurs. If the lag is long (>200 years) the response will not be significantly excited if the problem is solved in time that remains to do so. I would think that the worry would lie in the lag being of the order of the problem, say 30-60 years as that could give rise to a strong, and so far hidden, response extending for another 30-60 years even if all the combustion stopped tomorrow.

    What, perhaps, is needed is a significant signal in known CO2 emissions that can be looked for in the record to show the lag time in any response mechanism that is in the current regime.

    Sadly I can not think of one, not even the Oil Crisis 1973 or a war, that would be likely to show this up. I do not know if general emissions are sufficiently well recorded to analyse the C02 record for any lag.

    Even if it is, then given that the atmosphere is out of balance due to the rapidity of the rise, one might expect a predominance of an “apparent” CO2 leading signal due to the effects of CO2 sinks, as the CO2 level moves from being a response more to the total emissions to an equillibrium where it reflects more the rate of emissions. Detecting a lagging signal might not therefore be feasible given the uncertainties involved.

    A possibility that such a response exists leaves us with the interesting prospect that until we make a significant dent in the emissions we might never know how bad the problem is.

    I apologise for being long winded and vague on the evidence but if a strong ~50 year C02 reponse to temperature exists then it would be very bad news and if it can not be ruled out then perhaps it should be factored in to the limits of its possible range.

    Comment by Alexander — 28 May 2006 @ 1:40 PM

  25. My apologies, I did not notice that I am the second Alexander , the long ramble about lagging signals by me.

    Comment by Alexander Harvey — 28 May 2006 @ 1:44 PM

  26. Here’s an interesting publication about Vostok ice leads and lags:

    Mudelsee, M., The phase relations among atmospheric CO2 content, temperature and global ice volume over the past 420 ka
    Quaternary Science Reviews 20 (2001) 583-589

    Comment by Wolfgang Flamme — 28 May 2006 @ 2:31 PM

  27. [Moderator: Nonsense deleted]

    I know that Vostok dD at most represents SH sea surface temperatures, but – although there were time shifts between SH and NH – the NH temperature variations over the glaciations/deglaciations were not that different.
    – I checked ice sheet growth over the Eemian, which is roughly compatible with Vostok dD (a lag of a few thousand years). This was measured by d18O in N2O, which I suppose represents global ice sheet growth.
    – As ice sheet growth was mainly over land and mainly over the NH, I suppose that NH temperatures were lower in the NH than in the SH during the glacials (and higher during interglacials, as there is more land, which warms faster).
    – If temperatures in the NH were lower during glaciations, then global temperatures were lower than measured as dD in Vostok. And the global temperature variation during the transitions were higher, but result in the same variation in CO2 changes.
    – Consequently, the result of temperature increases even gives less extra CO2 than in my previous calculations…
    – Btw, according to the Gerber model runs, most of the CO2 changes follow temperature changes already within 1-2 decades. Thus it is no wonder that such an effect is not measurable in the current CO2 and temperature trend. Only with fast changes like El Nino, a variation in CO2 increment follows temperature changes after some 6 months. Similar changes are measurable in plant growth.

    [Response: You miss the point about the LGM. The LGM temperature drop pattern is not a very good analog for global warming, since the interhemispheric asymmetry in the former is much greater than the latter, especially as equilibrium is approached. Which temperature do you want to pick to make your analogue? Some estimates of LGM SH midlatitude cooling are as little as 2-3C, putting them in the same ballpark as the temperature change from anthropogenic global warming. That would (naively) imply that if the feedbacks worked the same way you could get maybe 100ppm boost from the CO2 feedback. Maybe you’d even get more, since in the LGM you expose a lot of new forestable land as you deglaciate, tending to offset what the ocean might be doing. It’s really really hard to use the LGM as an analogue for what happens under anthropogenic global warming, but insofar as one is going to do it at all your numbers are way too optimistic. –raypierre]

    Comment by Ferdinand Engelbeen — 28 May 2006 @ 3:50 PM

  28. >think you missed that … bwe know what’s happening but our day to day lives are a struggle enough, and besides, what one person does or doesn’t do is insignificant. Get a life

    Huh? I’m trying to see how it what you say relates to what I wrote. I’m pretty sure that the only people I talked about were flavors of global warming denialists. I made a testable prediction of the next denialist line. Don’t see how that is such a terrible thing to do. Don’t know what is wrong with people doing what they can.

    Comment by Gar Lipow — 28 May 2006 @ 4:38 PM

  29. Re: #23

    First of all, here is a plot of montly CO2 concentration from Mauna Loa since 2000. There are two clear trends. First, there is a steady secular increase, which is signficantly described by a quadratic curve. This fit indicates a rate of increase

    R = 2.11 + 0.0952 (t – 2003.17)

    where R is the increase rate in ppmv/yr., t is the time in years. Second, there is an annual variation.

    We can subtract both the secular increase and the average annual variation, leading to a “CO2 anomaly,” which is plotted here. From this we see that the CO2 anomaly for Jan. 2006 is not at all out of line; in fact it’s very small. We can also see that Jan. 2005 had a rather large *negative* anomaly. Therefore the difference between Jan. 2006 and Jan. 2005 is large, constituting the rate for 2006 (from the above formula, 2.38 ppmv/yr) + anomaly for Jan. 2006 (small positive) – anomaly for Jan. 2005 (sizeable negative).

    However, most of the departure from normal of the Jan.2005 – Jan.2006 difference is due to the large *negative* anomaly from 2005. Hence the exaggerated growth of CO2 from one January to the next really says a lot more about how *low* the level was (compared to long-term trend) in 2005, than about how high it was in 2006.

    Comment by Grant — 28 May 2006 @ 5:46 PM

  30. re 27. I was trying to give examples of what people have said to me when I brought up the fact that global warming is out of control and is being driven by our greenhouse gas emissions. When they give up on trying to say global warming isn’t really happening, they’ve said there’s nothing they can do about it anyway which would matter. I agree with you that people need to do what they can to reduce their own emissions, even though it may seem to not matter. It’s a moral issue to do what we know is right, not wrong. It’s wrong to use fuel excessively with no regards for the many very serious consequences from a more rapid rate of global warming.

    Comment by pat neuman — 28 May 2006 @ 5:48 PM

  31. Ray, for those who have a single theory they keep reposting, tempting you to either rebut again or again swear off answering — perhaps RC could provide a linkable stock rebuttal page?

    Reminding the posters you’ve rebutted them before won’t stop them; new readers however need to see your early, patient, detailed, footnoted attempts to explain why such ideas aren’t supported in the research.

    Point being to educate new readers who can’t tell which of you to believe in the absence of any footnotes from either of you! (wry grin here). “Use the cites.”

    Comment by Hank Roberts — 28 May 2006 @ 6:27 PM

  32. To clarify, are these papers suggesting the warming may be underestimated because of stronger positive feedbacks in the carbon cycle, or were such feedbacks largely excluded from consideration in the IPCC projections?

    Also, I understand there have been studies assessing the effect of CO2 fertilization under real world conditions, but I wonder if there’s been much follow-up on the effect warming will have on long-term sequestration by phytoplankton, and how quickly that might become a factor. This was the last I saw on diatoms.

    Comment by Alex — 28 May 2006 @ 8:45 PM

  33. Alex, try these (papers citing the article in Science)

    Comment by Hank Roberts — 28 May 2006 @ 10:52 PM

  34. I would just like to remind all posters that they should always carefully review their posts before submitting them. Real Climate have provided a nice mechanism for this process.

    A submission may be clear in your head, but, sometimes a crucial letter, word or sentence may be missing causing confusion and resulting in to and from posts that would have been unnecessary if the originating post was correctly submitted.

    Pat, I think your post 21 had something missing, I feel you missed a sentence to establish the context for the last paragraph. Also I do not like acronyms, excepting those that are widely understood, for example I am not sure what “bwe” means. :-)

    Comment by Lawrence McLean — 28 May 2006 @ 10:53 PM

  35. Re: 30

    >When they give up on trying to say global warming isn’t really happening, they’ve said there’s nothing they can do about it anyway which would matter. I agree with you that people need to do what they can to reduce their own emissions, even though it may seem to not matter. It’s a moral issue to do what we know is right, not wrong. It’s wrong to use fuel excessively with no regards for the many very serious consequences from a more rapid rate of global warming.

    Ah. I’d agree with the provision that it is more collectively wrong than individually wrong. Yes there are things one individual can do. But mostly there are things we as a society can do. I can bicycle when practical but I can’t take a train in my town cause there are none.

    Similarly decarbonizing the grid will be a collective, not an individual choice. A few well-to-individuals can buy hybrids and convert them to plug-in hybrids on their own, or even buy expensive electric cars. But until these are massed produced, available at the lot these won’t be an option for most of us. And so on. So it is not a question of individual guilt – it is a question of social choices.

    Comment by Gar Lipow — 28 May 2006 @ 10:54 PM

  36. RE 28: It seems to me that in the anomaly graph there is also some signal (i.e. a period of about 3 years). Of course, the time series is far too short to be convincing, but still it does not appear like just random noise. On even more shaky basis there might be a relation to the Dow Jones index ( which purportedly is somehow dependent on industrial activity level. Some broad trends appear to be coincident.


    Comment by Pekka Kostamo — 28 May 2006 @ 10:55 PM

  37. Re: #36

    I too think the data (the “CO2 anomaly”) is not just random noise. However, the point I was really driving at is that the change from Jan. 2005 to Jan. 2006 is definitely *not* unusual, given the behavior of the CO2 concentration since 2000.

    As for an approximately 3-yr. period in the CO2 anomaly, it’s best to look at the entire time series. I took the whole montly data set from Mauna Loa and generated a new curve in the same manner: subtract from the data a quadratic secular trend and the average annual variation to generate the “CO2 Anomaly.” The result is plotted here. Note that these are *not* the same anomalies plotted before, because the quadratic secular-trend curve which has been subtracted is that based on the entire time series, not just the series since 2000.

    The most notable feature is the precipitous drop in CO2 anomaly in the early 1990s. This was discussed before; posts suggested as possibilities an association with el Nino, as well as with the collapse of the Soviet economy.

    There are visible signs of an ~ 3-yr. period throughout the time series. A Fourier power spectrum is shown here. The most notable feature is the tall peak at very low frequency, which does *not* correspond to any real periodicity. Note there is a significant peak at frequency 0.275 cycle/yr., corresponding to period 3.63 yr. However, this peak could be indicative of a period, or it could indicate only a “characteristic timescale.” It could even represent neither, being only a manifestation of the “red noise” character of the CO2 anomaly curve. In fact the interpretation of peaks in a Fourier power spectrum — especially at low frequencies — is a *very* tricky business (Foster, G. 1996, Astron. J., 111, 541).

    Comment by Grant — 29 May 2006 @ 12:48 AM

  38. I was unaware that temperatures could be derived from ice core data. Could I have a link to an explaination of “dD?” Is this a derivative, or a delta? what is ‘D?’

    Comment by jhm — 29 May 2006 @ 7:49 AM

  39. >37
    jhm, here’s a quick answer, and an example of how you can find such answers.
    Read just the bit I quoted below for the answer to your question; see the whole paper for a good explanation.

    This is from the first hit produced by Google Scholar using this string:

    +temperature +”ice core data” +dd

    Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

    JR Petit, J Jouzel, D Raynaud, NI Barkov, JM â�¦ – Nature, 1999 –

    Ice cores give access to palaeoclimate series that includes local
    temperature and precipitation rate, moisture source conditions,
    wind strength and aerosol fluxes of marine, volcanic, terrestrial,
    cosmogenic and anthropogenic origin. They are also unique with
    their entrapped air inclusions in providing direct records of past
    changes in atmospheric trace-gas composition….

    The ice record
    The data are shown in Figs 1, 2 and 3 (see Supplementary Infor-
    mation for the numerical data). They include the deuterium content of the ice (dD ice, a proxy of local temperature change), the dust content (desert aerosols), the concentration of sodium …

    That’s been cited by 848 subsequent papers.

    I suggest you read the whole thing, search for it with Google Scholar.

    Comment by Hank Roberts — 29 May 2006 @ 8:22 AM

  40. About the ice cores, There is a connection between isotope rates and temperature but especially in (Ant-)Arctic areas also with precipitation. The complexity has been shown in this Ph.D thesis:

    “It is emphasised that isotopic variations in the hydrological cycle are complex, even in a relatively stable area such as Antarctica. Therefore one should be careful when quantifying climate signals over a period of several years on the basis of ice-core data.”

    However since the deep ice cores of Antarctica are very difficult to date with very few hard data points, Jouzel et al (EPICA Dome C) and Petit et al (Vostok) appear to have a used rather simple algoritms to wiggle match precipitation rate with isotope ratio and age. At least this appears when the “layer thickness” is correlated with the isotope ratio. r2>95% That’s highly improbable and it seems to proof direct dependency, or circular reasoning, so to say. Consequently, the variation that Michael Helsen identifies would have definite implications for both chronologies and temperature interpretation.

    For instance, Look at the near identical shape of the last spikes of both deuterium and clearly lagging CO2 (dD). Assuming normal second or higher order response characteristics, this strongly suggest a near simultaneous start.

    Comment by Andre — 29 May 2006 @ 10:11 AM

  41. RE #36

    Pekka, many thanks for the link to that fascinating chart. It tells much about the industrialization of the US before and after the WWII but it does not have much direct, certain relationship to atmospheric CO2 concentrations. Certainly, the IT, industry added a lot of growth and gambling to world stock trading. However, a graph of US or world consumption of coal, oil and gas will track with the upward momentumn of Wall Street.

    I will post some data on post-1981 global fossil fuel production in a later submittal. Thanks again for this unique piece of historical record.

    Comment by John L. McCormick — 29 May 2006 @ 10:33 AM

  42. What would be the current absolute temperature increase of the atmosphere,
    with respect to the above :

    “Both papers conclude that warming in the coming century could be increased by carbon cycle feedbacks, by 25-75% or so”

    Would like to read IPCC trend compared to the papers suggested increase. in degrees K.

    Comment by wayne davidson — 29 May 2006 @ 11:45 AM

  43. This page ( does not render properly in Opera, on a PC running XP. Figure A sometimes partially appears, and there’s a Figure B? I usually don’t have problems with this site in Opera.

    As to the feedbacks: Is it just me, or is pretty much every scientific (as opposed to political) estimate of the rate of climate change an underestimate?

    Comment by Brian Gordon — 29 May 2006 @ 1:39 PM

  44. re 35.

    I still think it is individually wrong to use fuel excessively, and there should be individual quilt for doing that. Two summers ago I visited a place that makes extravagant yachts that use enormous amounts of fuel. Their business was and probably still is booming.

    Comment by pat neuman — 29 May 2006 @ 5:59 PM

  45. Re #40: Andre, it appears you saw what you wanted to see in that dissertation. It simply asserts that it is more reliable to average temp data over several years, i.e., temp data plotted for individual years will tend to have larger error bars than a running average. Is this any sort of surprise? Do any scientific conclusions relying on ice core data depend on having precise temps for individual years?

    Comment by Steve Bloom — 29 May 2006 @ 7:57 PM

  46. Methinks arguments and speculation regarding atmospheric Carbon Dioxide will continue for some time. Regardless of possible climatic effects, in my opinion an overage of pollution alone is sufficient justification for burning less fossil fuel. Another justification is to cool off the oil wars.

    A combination of Net Zero appropriate architecture and plug in hybrid vehicles could quickly cut carbon emissions in half or more. Visit and read about Net Zero architecture with photovoltaics.

    Comment by Mark Wiener — 30 May 2006 @ 1:19 AM

  47. Re: #46

    I do not reject your support for Net Zero architecture and plug-in hybrid vehicles. But, I do urge you and others sharing your view to dwell on some of the real facts of life in America and likely all developed nations.

    1) most all of us are in debt up to our ears and are still paying the mortages on our 64 million owner-occupied dwellings. So, we are not about to put a “FREE” sign (who could afford two morgages?) on the lawn and build a Net Zero home.

    2) we drive our cars, SUVs and whatever we own, for about 10 years on average. To abandon our car for a hybrid (even if our line of credit still has some cash available) will flood used car lots with cheaper cars the less wealthy among us will purchase and drive.

    3.)there is no way, no way at all, to “quickly cut carbon emissions in half or more”. That regrettable fact deserves some attention when contributors wing all kinds of carbon-cutting suggestions without trying to imagine and help us see how a credit-strapped America will respond or – even how impractical it might be to plant trees without having, in place, a means to water them.

    I could go on for days with examples of the “lets do this or that” as if the average Joe and Jane are eager to spend big bucks on a “solution” they have no clue will make a difference.

    Personal choices will only go so far but mega-decisions driven by an almost-martial law attitude will start moving the Northern people towards the 60 to 70 to 80 percent carbon reductions needed to help our children survive.

    by John McCormick

    [Response: It’s because of the capital life issues you raise that it’s so important to get moving on putting the right market signals in place right now. Putting strong market incentives in place now will assure that emissions will start to go down in the next 20 years as capital assets are retired and replaced. It would have been better to have started this 20 years ago, but better late than never. –raypierre]

    Comment by John McCormick — 30 May 2006 @ 2:24 PM

  48. Re #47 Raypierre is of course right, that we are currently making big infrastructure changes, in the US and elsewhere. A house or building from 2010 will stand a long time, a car from 2012 will run for a long time, so we want them to be as energy efficient as possible.

    That said, I suspect the typical American could reduce energy use some 10% fairly easily. During the California electric crisis, we cut electricity use 10%, and those interviewed for TV news said, I didn’t really do anything, just turn off the light when I left the room and turned off my computer when I wasn’t using it and … Perhaps carpooling or taking public transit once or twice a week, or taking the train or bus for vacation rather than the plane, and living a little more consciously in the house. Then the policy people and the technology people could work a little less feverishly to find solutions (though reducing carbon emissions 60% or more will still be hard).

    Comment by Karen Street — 30 May 2006 @ 6:54 PM

  49. RE #48

    Karen, power control areas are 133 electric grid rings that connect regional electric power to regional demand across the nation. They are connected one to another and are the means to avoid a widescale blackout if a plant or transmission line goes down. Perhaps you know this but not many people have any idea how fragile is the US electric grid now.

    Looking to a possible near-future crash program to reduce US CO2 emissions, power stations will be primary targets. Of the 1,000+ gigawatts of generating capacity, 60 percent are coal, oil,gas-fired and emitted, in 2004, 2.3 billion tons of CO2, or, 32 percent of US 7.12 billion tons.

    Now, big infrastrcuture changes come into play. The top 14 power control areas, in terms of CO2 emissions, emitted about one billion tons of CO2 from their total 212 Gigawatts of capacity. They are all within a 300 mile radius of Louisville. Bottom line: 20 percent of US generators supply electricity to about 100 million customers and deliver 14 percent of US CO2 emissions to the earth’s atmosphere.

    I say this as an avowed environmental activist with 30 years of lobbying for the coal strip mine reclamation law, clean air act and acid rain control and against utility deregulation.

    RealClimate may not be a suitable page to discuss engineering challenges but we do have to pay some attention to those pesky numbers behind all of our hopes that we can somehow make the problem of climate change become more manageable by cutting 60 or 80 percent of our carbon use.

    I too believe we can shave 10 percent off our individual energy use. That is a down payment on the more than $200 billion in infrastructre replacement the fractured and recalcitrant electric utility industry faces.

    Comment by John L. McCormick — 30 May 2006 @ 8:20 PM

  50. Re #27 (comment):

    Raypierre, I have purchased (again…) the two articles in GRL to know the details of what was done. For the Torn and Harte paper, which used Vostok data, it is indeed clear that the difference between straight-forward local temperatures (derived from dD) and SH temperatures (derived from corrected dD) over 360,000 years is quite large.

    This gives 9.1 ppmv/K for local Vostok temperatures (over the full 420,000 years, I calculated 8.1 ppmv/K), against 14.6 ppmv/K for the SH. For the LGM-Holocene transition, the (probably SH) slope is 17 ppmv/K.

    But what happened in the NH? That is the important question. For what I have read in the past, the NH has much larger temperature swings between glacials and interglacials, due to more land, which means more ice building during ice ages and higher temperatures in interglacials. But higher NH temperature variations implicate higher global temperature variations and a lower response of CO2, as these are globally known (within the error margins of the ice cores…).

    I didn’t find NH data which corresponds to the full Vostok time record, but the Greenland ice core data span the last glacial, including the LGM-Holocene transition. From the Greenland ice core data, one can derive a local temperature change of ~20 K between the LGM and the Holocene (with an extra peak just before the Younger Dryas), derived from d18O in ice. The corresponding NH (or global?) temperature according to the univ. of Leeds, item 7.5, might be around 10 K between LGM and Holocene. Global temperature shifts then would have been around 8-9 K (with the corrected SH temperature swing and assuming the “Leeds factor” as NH temperature). The change in CO2 levels in the same period is ~80 ppmv, that gives a slope of ~10 ppmv/K. A little more than I derived from the full Vostok (local) temperatures, but less than what is calculated by Torn and Harte.

    If we assume that the 10 ppmv/K is right, then the IPCC model range would be 1.58-5.3 K for 2xCO2. The lower end still seems benign, the middle range (3->3.3 K) still critical and the higher range still a disaster, with or without CO2 feedback…

    I haven’t checked the Scheffer ea. data yet (based on MWP-LIA changes), and rapid changes due to ENSO events may be of interest too.

    Comment by Ferdinand Engelbeen — 31 May 2006 @ 9:38 AM

  51. Re 49, 48 & 47. “Dr. Hansen isn’t running for office. But Mr. Gore might be, and even if he isn’t, he hopes to promote global warming as a political issue. And if he wants to do that, he and those on his side will have to learn to call liars what they are.” Washington Post.

    Re 49, 48 & 47. Shaving 10% of individual energy use will make no difference what so ever. Here in Europe every man women and child uses twice their share of the world’s energy. Reducing that by 10% would still leave we Europeans using 80% more than is fair. In the United Sates the figure is 5 times their share and reducing that by 10% would leave each American with 350% more than they are entiled to.

    Since Kyoto was first proposed, the UK has stabilised its total CO2 emissions at around 600 million tons per annum. Meanwhile the US has increased its emissions by around 700 million tons. In other words, even if we in Britain had stopped burning any fossil fuels, global greenhouse gas emissions would have increased because of the US!

    The good news is that if the US did halve its energy consumption then the standard of living in the US would still be above that of the UK, which is perfectly adequate for a civilised society.

    The bad news is that both the UK and the USA will have to go even further. However, it will be forced on them by soaring oil prices now that we have passed Peak Oil. However, we must have a global agreement to cut fossil fuel use, otherwise when we have used all that expensive oil we will be roasting in a hell of our own making.

    Comment by Alastair McDonald — 31 May 2006 @ 11:15 AM

  52. Here’s a source I hope the RC contributors or Coby for the ‘ill-considered’ list will check. It may be one of the places some of the odd and unsupported ideas come from — for example the claim that CO2 is already absorbing all the infrared it can. This is all footnoted to early 1990s sources on the site.

    Comment by Hank Roberts — 31 May 2006 @ 1:57 PM

  53. To those who argue we cannot make quick emissions cuts, for example #47:

    > 3.)there is no way, no way at all, to “quickly cut carbon emissions in half or more”. That regrettable fact deserves some attention when contributors wing all kinds of carbon-cutting suggestions without trying to imagine and help us see how a credit-strapped America will respond or – even how impractical it might be to plant trees without having, in place, a means to water them.

    Of course there is a way – there are many ways. (I do agree with Mr. McCormick’s contention that the US debt will be a very major problem, because it will severely limit the federal government’s ability to drive or finance change.) It’s just that we don’t like any of them, because they change the current economic structure. Taxes could go way up on GHG-producing products, auto fuel efficiency could be mandated at a very high level, new houses could be net contributors to the grid, etc. Americans are unwilling to consider these options because they are “left-wing,” “socialist,” or in some other way are thought to inhibit individualism. But there are lots of ways we could immediately and drastically reduce our emissions. Or, we could wait for climate change to reduce our emissions by reducing our numbers. Pay now, or pay later. Maybe with your children’s lives.

    Comment by Brian Gordon — 31 May 2006 @ 2:57 PM

  54. Re #51 – I don’t see how you define what is a “fair share” of the world’s energy. Are you referring to average individual energy consumption? You then remark on how Europeans and Americans use more than their “fair share” – meaning others use less, and if all people used their “fair share” we would still be at the same level of energy use, right? I don’t understand this at all. Also, it appears you define an “adequate” standard of living for a civilized society as that of the UK. Why is this? Could you give us some insight into the calculus you are using?

    Comment by Tom Boucher — 1 Jun 2006 @ 10:29 AM

  55. Re #54 The figures I quoted were what I remembered from a BBC broadcast, so they may be inaccurate or garbled. If you go to Fig 5 on page 4 of this PDF file from a WWF site, you will see that Western Europe’s ecological footprint is five times that which is sustainable, and North America’s is nine times. . It seems that the average foot print is two global hectares, so as you point out even if Britain and the US restricted themselves to the average then the world would still be consuming at twice the sustainable rate. OTOH if both N. America and W. Europe restriced themaselves to the current average, there would be a huge reduction in the resulting average consumption.

    The main point is that NA and WE consumption is unsustainable and it will have to be curbed by governments, otherwise it will be enforced on us by India and China grabbing thier share. How can you stop them in a free market?

    As far as the UK having an adequate standard of living, in fact it is now too high. A recent survey revealed that compared with 50 years ago when 80% of people were happy, the figure is now 30%. It seems clear to me that we are now too rich for our own good.

    Comment by Alastair McDonald — 1 Jun 2006 @ 11:32 AM

  56. At what point do we consider geoengineering as a response to abate global warming? I am specifically thinking of placing screens in space to regulate the amount of sunlight reaching the planet and/or disbursing aerosols above the troposphere to reflect away sunlight. Moreover, what are the risks to the biosphere from such schemes? I would greatly appreciate it if you could direct me to the literature on geoengineering and climate change.

    Comment by George — 1 Jun 2006 @ 11:49 AM

  57. >geoengineering
    Maybe a big cloud of coal dust launched into space (wry grin). That’d show those photovoltaic people, cut their efficiency ….

    Comment by Hank Roberts — 1 Jun 2006 @ 11:56 AM

  58. Remember natural variation happens. Imagine trying to undo a big cloud of dust in space blocking sunlight, or a big cloud of sulfates in the stratosphere, if the sun happened to become a bit less bright afterwards.

    The good thing about fossil carbon is it could be used in a way intelligently designed — not so much as to push the climate into warming, and enough to avoid slipping into cooling.

    Apparently we did that well until about the 1600s.

    Comment by Hank Roberts — 1 Jun 2006 @ 12:15 PM

  59. Geoengineering is not the answer. Why geoengineering won’t work:

    1. Governments, corporations, and individuals will create what they want, not necessarily what the planet needs, just as occurs now. Planet-scale geoengineering involves worldwide cooperation and agreement – we can’t even agree now that global warming is a threat, never mind agreeing to something as minor as Kyoto, never mind agreeing to governmental environmental control.

    2. When you don’t know all the complexities of your life support system, it is foolish to experiment with it. I doubt we will ever know enough to be able to accurately control our environment (though we may soon be forced to try) because it is an evolving system, and because the complexity of the earth’s systems is truly staggering.

    3. Planet-scale geoengineering is completely out of harmony with the natural world – it makes us God/gods. It assumes that we have a right to live at any cost, but no other species unless it suits us. This is a common developed-world/Judeo-Christian belief, and it is one reason we are in such trouble now. We currently have the creative and destructive powers of minor gods, but not the wisdom to know how to use those powers.

    Comment by Brian Gordon — 1 Jun 2006 @ 2:20 PM

  60. Geoengineering may be in the future, as a necessary evil. I agree with Brian’s points above, but I would say this:

    Geoengineering could work, we are resourceful and clever creatures. The problem is it would take a few planets and a few multi-decade trials before we would get it right. Imagine the waste disposal problem, getting rid of the many spoiled planets created in the learning process…

    I can’t help smirking a bit at the irony involved. Surely the geoengineering solutions would be tested out on all those wonky computer models, right? This is what the sceptics think is the prudent course, ignore the model warnings but then design and execute massive planet wide experiments based on same.

    Comment by Coby — 1 Jun 2006 @ 2:54 PM

  61. “Fix Venus and Mars First” should be our approach.

    Sunshade between Venus and the Sun; mirror on the far side of Mars, at the Lagrange points, eh?

    Comment by Hank Roberts — 1 Jun 2006 @ 3:19 PM

  62. George wrote in comment #56: “At what point do we consider geoengineering as a response to abate global warming? I am specifically thinking of placing screens in space to regulate the amount of sunlight reaching the planet and/or disbursing aerosols above the troposphere to reflect away sunlight. Moreover, what are the risks to the biosphere from such schemes?”

    How would you like to take conscious control of your liver, your kidneys, your intestines, your lungs, your lymphatic system, etc, and direct their functioning at the cellular level with your conscious mind? And once you do so, you never get to stop — if you don’t consciously direct them and coordinate them to perform their biological functions at every moment, they’ll simply stop, and if you make an error in your instructions to them, they will fail and you will die.

    Do you think that “you” — your conscious mind — could do a better job of directing and coordinating the functions of these organs than “nature” does?

    With that in mind, do you think that human “engineers” can do a better job of “running” the Earth’s climate, ecosystems, and the biosphere than “nature” does?

    Someone once said of George W. Bush that “he was born on third base and thinks he hit a triple”.

    Sometimes, something like that seems to me to apply to the human species. We were “born” into a rich, diverse, wonderful living Earth, and have been enjoying the vast bounty that it freely bestows upon us for thousands of years, and we have come to think that we are “gods” and we can take over and run the whole show better than billions of years of evolution have made the whole show quite capable of “running” itself without our “help”.

    What hubris cometh before a fall!

    Comment by Doug Percival — 2 Jun 2006 @ 9:37 PM

  63. Re #60 (“I can’t help smirking a bit at the irony involved. Surely the geoengineering solutions would be tested out on all those wonky computer models, right? This is what the sceptics think is the prudent course, ignore the model warnings but then design and execute massive planet wide experiments based on same.”):

    What makes it even more ironic to me is that it seems like you have to know what is going on with the climate due to greenhouse gases to way higher precision in order to do some sort of geo-engineering to counteract act it than you do to counteract it by simply reducing or sequestering greenhouse gas emissions. (And, of course, then in addition, you have to know to high accuracy the effect that your geo-engineering solution will have…and how these effects will interact.)

    Another irony is that many of the people throwing out these ideas are of the libertarian or conservative bent who complain about the evil’s of government intervention and regulation, the U.N., and such. However, their proposed solution seems to be one that can only work on a big government scale with massive amounts of international cooperation. By contrast, while approaches like Kyoto do involve international agreements and government action, they can be (and are being) implemented in market-based ways such as through emissions trading so that they are much more flexible and market-oriented approaches to finding solutions.

    Comment by Joel Shore — 3 Jun 2006 @ 11:43 AM

  64. Little of what has been said here so far speaks to the viability of geoengineering solutions to the potential of run-away global warming. It is should also be stressed that we have already altered the biosphere through excessive carbon dioxide emissions. Geoengineering could be a rational means to stablize the environment. In the long run, I agree humans must institute appropriate regulations of its changes to the planet.

    Comment by George — 3 Jun 2006 @ 5:40 PM

  65. Thanx for this entry on positive feedbacks (I’ve been away from the net for a few weeks). I understand that scientists can only work with stuff they can work with (quantify, etc), which doesn’t mean other stuff isn’t happening or might not happen.

    As people living on this planet, OTOH, we should follow the prudent route of thinking the worst could happen, and do whatever we can to stave it off at the personal level; at home, work, school, church; at the various levels of government from local to national to international. I can’t think of a better way for me to spend my spare time…..

    I’m reading Cliffnotes Statistics (gearing up to teach statistics again after a decade), and came across this on p. 70: “A small, but important real-world difference may fail to reach significance in a statistical test. Conversely, a statistically significant finding may have no practical consequence.”

    [Response: Welcome back. I was wondering why we hadn’t heard from you in a while. When looking at significance tests, make sure to keep an eye out for the distinction between those that assume a Gaussian underlying distribution and those that are independent of the underlying distribution (or rely on some a priori estimate of it). Also, one must keep in mind that if one looks at a hundred results, it’s a pretty sure bet that one of them will be significant at the 1% level. –raypierre]

    Comment by Lynn Vincentnathan — 5 Jun 2006 @ 10:27 AM

  66. RE: #64, George mentions a “potential run-away global warming”. It is more than a potential if we continue to “engineer” the planet’s atmosphere. That said, correcting our folly will never (time, money and confidence level are not there) include a geoengineering solution.

    We must get this thread back onto the reality track

    Comment by John McCormick — 5 Jun 2006 @ 1:03 PM

  67. re #52 by Hank Roberts
    I don’t understand your dismissing T.J. Nelson out of hand. Because he had some cited references from ancient 1992? Is the science of Beer’s Law, e.g., now outdated? Is it “odd” just now, or was it always odd?? Actually, while I don’t have the bona fides to credibly assess, I found his article extremely learned, intuitively believable, and devoid of snide and strident comments. The latter, btw, while cute, unfortunately detract from what otherwise what might be valid science.

    [Response: A lot of rubbish is written in a way that seems learned. The problem isn’t that science has changed, but that a lot of the material on the web site mentioned in #52 is based on a fundamental misunderstanding of basic physics. For example, it’s not Beer’s law that is at issue but that the greenhouse effect depends on how much radiation gets out the top of the atmosphere for a given surface temperature, and that relies not on the saturated part of the CO2 band but the unsaturated part in the wings. The reference to the old “1990’s” literature, I think, was not meant to imply that the fundamental physics has changed, but that the site refers to “old” skeptics arguments that have for the most part fallen out of fashion. Skeptics keep recycling lies and misleading statements long after they’ve been debunked, but even these arguments wear out after a while, so the skeptics have to move on to new and better ways of misleading the public. –raypierre]

    Comment by Rod Brick — 7 Jun 2006 @ 11:58 AM

  68. Maybe i didn’t understand the rules? I didn’t want to discuss economic impacts, etc. but it still apears we have an elephant in the room that isn’t being considered in any of the articles here or wikipedia.
    My concern is we appear to be releasing between 1% (absolute best case) to 3-5% of solar influx in hydrocarbon and nuclear heat sources, (at the moment, growing steeply). Since it appears that orbital variations can account for about 6.8% solar variation,
    ( ) aren’t we talking about a significant challenge to Gaia?
    (and everybody else that lives on this rock?)
    Wasn’t trying to be a smartass, really think this should concern us?
    Please be so kind as to educate me if my ‘facts’ err?

    [Response: Your energy numbers are all wrong. A little more care in looking around on the web would have given you reliable numbers. These are easy numbers to get, so there’s no excuse for being so speculative. From Eric Weinstein’s Physics World, ( ) the world power use is 1.28 x 10**13 Watts. Using the surface are of the Earth, this amounts to .025 Watts per square meter. Absorbed solar radiation is on the order of 250 Watts per square meter. The heating from energy use, averaged globally, is utterly insignificant compared to solar energy, and also unimportant compared to the indirect effect of industry via the CO2 radiative effect (about 4 W/m**2 for a doublling). As for your comment regarding Milankovic (also partly wrong in the numbers because you fail to distinguish seasonal local variations from global means) I don’t understand that at all. –raypierre]

    Comment by allun — 14 Jun 2006 @ 7:29 PM

  69. I’m getting into this a bit late, and guess what, I haven’t read it all yet. At this level of conversation I’ll stick to asking “questions”.

    Considering that H2O is a, or ultimately the, major GG, will we see a turnaround in runaway greenhouse (the point where natural forces dominate, and even total economic collapse won’t stop it) while there’s still more water to evaporate from the oceans? What natural forces will stop it before that point? Could this mean the end of all life on earth? Are we looking at why we’ve never been (provably) contacted by ETs, because they all followed similar paths and never made it much beyond us?

    Comment by Dan Robinson — 14 Jun 2006 @ 8:02 PM

  70. No Venus runaway possible here. There is a post on this site specifically about Venus, you should have a look.

    Comment by Coby — 14 Jun 2006 @ 11:34 PM

  71. Re 69 & 70 I don’t think Dan was proposing that Earth would turn into a Venus. They are very different. Venus is heated by carbon dioxide and kept cool by sulphur dioxide clouds. Earth is heated by water vapour and kept cool by water clouds. Thus Earth has a built in thermostat which prevents it heating above about 40C. The greater the greenhouse effect, the thicker the clouds that are produced. It is a negative feedback. That is why life has existed for 3,500,000,000 years :-)

    But it has only held on by the skin of its teeth on several occasions, and one of these is about to occur again, when the Arctic sea ice melts and Arctic temperatures jump by 12 C or more, just as they have in Svaldbard this year :-(

    [Response: I’m not aware of any built in thermostat mechanism that keeps the Earth below 40C. In fact, I’ve run plenty of simulations that get warmer than that, given enough CO2. What did you have in mind? Lindzen’s paper from the 1980’s is based on incorrect radiation, questionable models of convection and an unrealistic assumption about the vertical distribution of water vapor. –raypierre]

    Comment by Alastair McDonald — 15 Jun 2006 @ 5:12 AM

  72. raypierrie,
    Excuse me? You may be right, however, most of my numbers cames straight from this site, and ( ). My estimate on insolation is not really speculative, as i used the solar constant (429 btu/sq.ft./hr.) shining on a normal disk of earth radius – 35% reflectance, (obtained from my Halliday & Resnicks), and must only be a quite high ballpark. The reality has to be (much?) lower. Your reference to ( ) doesn’t seem to address this at all?
    Still, it would be great if you’d show me where i err, as i really don’t see how seasonal variations, due to incidence angle, affects the integrated whole earth energy balance.

    [Response: Ray is right. The solar energy incident on the Earth’s surface is the solar ‘constant’ (~1365 W/m2 – can we stick to metric units please?) divided by 4 (to account for the surface area of the disk vs. the sphere) and multiplied by the co-albedo (~0.7 – your 35% albedo number is slightly too high), giving around 240 W/m2. Total energy consumption is around 412 quadrillion Btu / yr = 412*1055*10^15/(5.1*10^14 area of the earth)/(3600*24*365 seconds in a year) = 0.027 W/m2 – 4 orders of magnitude smaller…. -gavin]

    Comment by allun — 15 Jun 2006 @ 5:36 AM

  73. gavin,
    I’m an engineer. We lack the large brains inherent in earth scientists, so we deal in complexity reductions. Let me attempt one here? We live in a large insulated box, that has an internal and external heat source? This box has achieved a thermal equilibrium of sorts. We’re at the moment increasing the r factor of the boxes insulation at the same time releasing 300-500 quadrillion btu’s/yr of extra internal heat source. Lets not quibble about magnitude, the fact that we’re messing with (thank you for the 4 orders of magnitude, some relief there!), a (moderated by feedback?) equilibrium still concerns me. (But less now, thanks!)
    And i still don’t see any way seasonal variations effect an integrated whole earth balance.

    Comment by allun — 15 Jun 2006 @ 6:49 AM

  74. Ray, surely you are aware of my scepticism of the models. It is the paleoclimatic record which shows that the global mean temperature has never risen above 40C. Moreover, if Lindzen were right with his “Iris theory” then the warmth of the Eemian could never have happened. My ideas are original, but not new. I have since discovered that they had already been proposed by
    Ou ,
    Wally Broecker (of course) , and G.C.Simpson [
    (1928). “Some Studies in Terrestrial Radiation.” Memoirs of the Royal Meteorological Society 2(16): 69-95.,
    (1928). “Further Studies in Terrestrial Radiation.” Memoirs of the Royal Meteorological Society 3(21): 1-26.]

    [Response: I’m not aware of geological evidence that would preclude temperatures over 40C ever having occurred over the past 3.5 billion years. There’s no positive evidence for such warm temperatures, but it’s too strong a statement to say that it couldn’t happen. The prevailing theory for the generally moderate temperatures over the long term is the CO2 weathering thermostat, though there are suggestions that a methane regulation mechanism might have been dominant instead before the oxygenation of the atmosphere. That’s very different from saying the temperature wouldn’t exceed 40C no matter how high the CO2 or methane got. The Broecker press release you linked states only that he thought water vapor reductions could have accentuated LGM cooling (more precisely stated, that reductions in relative humidity could have lead to more cooling than the standard models). This could well be true, but not on the basis of Broecker’s evidence, which rested on a rather faulty interpretation of the Andean mountain glacier data (see my GRL paper on Huascaran isotopes). In any event, there’s no suggestion there of a thermostat at the high end. Ou’s paper rests on a highly questionable assumption regarding maximization of entropy production., and in the end is a kind of low-cloud thermostat mechanism; he does predict a limitation on maximum temperature, but neither the reasoning nor the predicted behavior of low clouds is borne out by any cloud-resolving dynamical simulations I’m aware of. None of these things have anything to do with the matters regarding radiative transfer fundamentals you used to bring up earlier in the history of RealClimate. I haven’t read these two old Simpson papers, which date back to the early days of radiative transfer when people were still sorting out some very basic points, but if they deal with the subject matter I think they do, it is discussed and disposed of in Goody and Yung’s book, under the heading of “Simpson’s Paradox.” –raypierre]

    Comment by Alastair McDonald — 15 Jun 2006 @ 12:29 PM

  75. On another thread on this site, I asked for the data showing that we (humanity, civilization) have 10 years to make significant reductions in GHGs; after that, the degree of climate change will (sooner or later) be sufficient to end life and lifestyle as we know it. This thread seems a much more appropriate place to talk about that, as climate change inevitability is all about feedbacks and tipping points.

    Hank Roberts pointed me to this article:
    which was helpful. From the article:

    “The Earth’s climate system has great thermal inertia, yielding a climate response time of at least several decades for changes of atmosphere and surface climate forcing agents [Hansen et al., 1983].” p. 2

    Is this still considered to be true? If so, then the Arctic is melting due to GHGs from decades ago. Uh oh. Or pollution (ozone, methane, and soot) as the authors suggest?

    For the Arctic sea ice to melt, its temperature must rise above the freezing point of sea water. For that to happen, the ice must absorb energy to rise to the freezing point, then must absorb more energy to change state. If we weren’t measuring the ice temperature/heat content, we don’t know how long the time lag has been before the ice actually started melting. Has anyone been measuring the temperature of the sea ice? More from the article:

    “Satellite data indicate a rapid decline, ~9%/decade, in perennial Arctic sea ice since 1978 [Comiso, 2002], raising the question of whether the Arctic has reached a ‘tipping point’ leading inevitably to loss of all warm season sea ice [Lindsay and Zhang, 2005]. Indeed, some experts suggest that “…there seem to be few, if any, processes or feedbacks that are capable of altering the trajectory toward this “super interglacial” state – free of summer sea ice” [Overpeck et al., 2005].

    “Could the Greenland ice sheet survive if the Arctic were ice-free in summer and fall? It has been argued that not only is ice sheet survival unlikely, but its disintegration would be a wet process that can proceed rapidly [Hansen, 2004, 2005]. Thus an ice-free Arctic Ocean may have implications for global sea level, as well as the regional environment, making Arctic climate change centrally relevant todefinition [sic] of dangerous human interference.” p. 24-25

    “We suggest that the conclusion that a ‘tipping point’ has been passed, such that it is not possible to avoid a warm-season ice-free Arctic, with all that might entail for regional climate and the Greenland ice sheet, is not warranted yet. Better information is needed on the present magnitude of all anthropogenic forcings and on the potential for their reduction. If CO2 growth is kept close to that of the alternative scenario, and if strong efforts are made to reduce positive non-CO2 forcings, it may be possible to minimize further Arctic climate change.” p. 25

    It seems that some experts think a tipping point has already been passed for the Arctic, and therefore, Greenland, while the authors of this paper do not. Further, they feel this tipping point can be avoided if strenuous action is taken immediately (see the last sentence of the quote). However, they make no claims of having scientific evidence to ‘guarantee’ this. From another article (sorry, I do not have the original reference):
    “In early 2004, a surprising course [sic] began to publicize the risk of one such event, the U.S. Department of Defence, the Pentagon, released to Fortune magazine its analysis of the security implications of “a plausible scenario for abrupt climate change.”

    “It suggested that it was plausible that the Gulf Stream could stall by 2010. This would be caused by rapidly melting polar ice changing the salinity of the ocean. The ice is fresh water and its release would push down on the more saline currents, slowing and potentially stopping the vast ocean conveyor belt of currents. If the Gulf Stream were to stall, the Pentagon study anticipated widespread social and institutional collapse as droughts led to collapses in food production, displaced environmental refugees pressed on other borders for resources, soil erosion increased and wind speeds across Texas picked up … The Pentagon concluded that the risks of climate change were more significant than the risk of terrorism.

    “To avoid the “tipping point” described above, we need reductions of [GHGs of] 80% by 2050, of 30% by 2020.”

    I don’t understand at all how reducing GHGs by 2020 and 2050 will avoid a tipping point that will occur in 2010? This scenario was described as “plausible,” and 2010 is only four years away; even if it’s not 2010, but 2020, surely there are enough GHGs currently in the atmosphere to accomplish this?

    Thanks for your patience…and let no one construe that passing tipping points is an excuse for doing nothing.

    [Response: The “tipping points” refererred to above are somewhat speculative but within the realm of possibility — though the “European ice age” response to a thermohaline shutdown begins to look somewhat less plausible as a consequence in light of recent thinking on the role of sea ice in past responses, though there may be other serious consequences of thermohaline shutdown. Remember, though, that if there are tipping points, nobody is sure precisely where the thresholds are, so reducing emissions at any time gives you a better chance of not having passed one. Moreover, it is highly likely that there are several thresholds in the climate — melting of Greenland, melting of the West Antarctic ice sheet, some major shift in El Nino (perhaps), desertification of the Amazon, clathrate release, carbon release from arctic soils, probably many more we haven’t thought of yet. Each of these would have a different threshold. The less far we go from the familiar climate range of the past two million years, the less likely we are to encounter something really bad. Thus, even if we couldn’t do better than stabilizing at 2xCo2, there are still a lot more impacts that will set in between 2xCO2 and 4xCO2, so it’s still worth the effort to stabilize at 2xCO2. I do hope we can do better than that. –raypierre]

    Comment by Brian Gordon — 15 Jun 2006 @ 5:18 PM

  76. “Re 69 & 70 (& 71) I don’t think Dan was proposing that Earth would turn into a Venus. They are very different. Venus is heated by carbon dioxide and kept cool by sulphur dioxide clouds.”

    Yes, actually I was thinking of a “Venus syndrome”, and for the moment, still am. Has the negative feedback effect of H2O clouds been proven to happen? I’m thinking higher temperatures, probably throughout the atmosphere, would mean H2O would have to go to a higher altitude to condense to clouds, putting a thicker blanket between us and the drier air above, maybe meaning the percent of cloud cover would remain about the same. Also (and maybe part of the cause of the previous effect) condensation to clouds causes heating, just as evaporation causes cooling. I’ll accept your view as long as all this has been considered.

    “That is why life has existed for 3,500,000,000 years”

    But keep in mind that in about that span of time, the sun has grown hotter by about 25% (James Lovelock), so all bets are at least in doubt.

    Comment by Dan Robinson — 15 Jun 2006 @ 10:06 PM

  77. Yes, actually I was thinking of a “Venus syndrome”, …

    Dan, please see Lessons From Venus , which explains why the Venus syndrome can’t happen here.

    [Response: At least not for a billion years or so. I should provide a clear disclaimer that the discussion Rasmus and I provided in the Venus article was based on clear-sky water vapor feedback. Nobody has brought clouds into the picture in a convincing way, and it’s a matter that badly needs to be rectified. It’s actually hard to rule out a runaway cloud-based greenhouse effect on Earth, because clouds are so optically thick in the infrared. I don’t think it’s at all likely, but whether it happens is a race between the cloud cooling and the cloud warming effect. The reason I say it’s hard to rule it out on first principles is that some of the parameter sets in the ensembles do seem to run away. These were just discarded for the most part, but they ought to be looked at so as to provide a better understanding of the physics involved in the runaway. (well, we don’t know whether it’s a real runaway, since the runs were stopped before equilibrium). As I said, I don’t think this is a likely scenario, and it’s probable that the runs with a “runaway” cloud feedback would fail to match 20th century temperatures. However, we’d learn something by finding out what was going on in those runs, and refining our picture of why we don’t expect real clouds to behave that way. On the other hand, given recent evidence of a very warm early Paleocene Arctic, I wouldn’t completely discount a surprise cloud warming effect we haven’t factored in. –raypierre]

    Comment by llewelly — 15 Jun 2006 @ 11:39 PM

  78. I think geoengineering (e.g., increasing polar albedo by large-scale spraying of titanium dioxide, possibly on some kind of flotation device for the polar seas) merits research as a component of our response to climate change. Of course it should not become an excuse to continue unsustainable carbon emissions, nor an excuse to cut climate research (as some deniers would argue). But, at the same time, geoengineering should not fall victim to the idea that “we shouldn’t play God;” alas we already are playing God via our carbon emissions.

    We should evaluate potential solutions primarily on their technical and economic merits. That doesn’t mean losing sight of Earth as our spiritual home, but it does mean not letting dogma become our primary guide.

    Comment by Ron — 16 Jun 2006 @ 5:30 PM

  79. Re: #78. Ron, I know from nothing about titanium or your idea (suggestion) to increase polar albedo by large scale spraying of titanium dioxide. You say it merits research as a component of our response to climate change.

    Here is what I know of the Arctic ice: it is melting rapidly. Over the past 30 years the annual average sea-ice extent has decreased by about 8 percent, or nearly one million square kilometers.

    Here is what I learned from a USGS 2005 report on Titanium Statistics and Information about the cost of titanium on the world market:


    Because of a significant increase in demand, prices of titanium metal products rose considerably. The year end unit value of titanium sponge ranged from US$3.55 to US$6.44 per pound in 2004, a significant increase compared with that of 2003. The yearend price range for titanium scrap also reflected market conditions, increasing to between US$3.80 and US$4.00 per pound in 2004 from between US$1.50 and US$1.70 per pound in 2003.

    So, titanium sponge ranged in 2004 from $7100 to $12,880 per ton and titanium scrap from $7600 to $8000 per ton. I wonder what it would cost to spread titanium dioxide on the Barrows airport runway?

    Comment by John L. McCormick — 16 Jun 2006 @ 10:33 PM

  80. Ray, thank you for your long response. I hadn’t guessed the cloud unknowns were of such importance to a potential runaway greenhouse effect. It helps that you mention the Arctic, where cloud warming is expected to outweigh cloud cooling. Now I’ve a question: Is Arctic cloud cover increasing?

    Comment by llewelly — 16 Jun 2006 @ 10:59 PM

  81. I gather from Raypierre’s comments that the recent study on the Arctic 55mya gave some rather alarming results. Is there any chance of a blog-post about the study, the results and what the implications may be? That would be extremely helpful!

    [Response: Writing an article on this is next on my queue. I’ve bumped it ahead of Part III of the circulations and warming post. Very, very interesting stuff. Those who want to get a peak at it should look for recent papers authored by “Brinkhuis” on –raypierre]

    Comment by Almuth Ernsting — 17 Jun 2006 @ 5:25 AM

  82. Ray,

    Please allow me to expand on a few points I made in my previous short post #74 by responding to your response.

    Lack of geological evidence for global mean temperatures ever exceeding 40C seems to me to be good grounds for assuming it to be true. Moreover, if temperatures above those levels had occurred in the past, then life as we know it would have been destroyed, as nearly happened during the PT mass extinction.

    As you say, mechanisms associated with atmospheric CO2 are generally regarded as having controlled past climates, but I an arguing, like Wally Broecker, that ” … most thinking has focused on water vapor changes as secondary; that is, as the earth warms or cools, evaporation rates change and the amount of moisture in the air rises and falls,” he said. “We opt to turn this thinking around and make water vapor the driver that changes global temperatures.” Although he was referring to Quaternary climates, the Principle of Uniformitarianism means that this hypothesis should also apply to all of Earthâ??s history. Since it does solve many problems, not least those posed by Veizer, then this should be seen as confirmation of its validity.

    My thinking is not based on what Broecker said in the Daly lecture. Like you, I only have the account from the press release. However, since the basis of my ideas is that rapid climate change is caused by the runaway effect of water vapour, I have to admit that Wally got there first. However, I go further than your view of his ideas, and claim that both rapid coolings and rapid warmings can be caused by that effect. All that is needed is the sudden formation of sea ice as happened at the start of the Younger Dryas, or a massive release of methane as happened at PETM event to trigger a cooling, or warming event, respectively.

    I gather from reading the abstract of your paper, (all that is readily availble to me at present,) that you do not deny that there was a reduction in humidity during the last glacial maximum. The drying of the atmophere during glacial periods is well known, but in a Science paper Maslin & Burns showed that it also happened in the Amazonian basin during the Younger Dryas. In a recent BBC TV program you could see where in the Greenland ice the Younger Dryas had ended, by the abrupt change in colour of the snow due to the ending of wind blown dust when the climate suddenly became wetter.

    [Response: I have my full Huascaran paper, like most of my papers, posted on my publications site. I wasn’t at the Daly lecture, but from the abstract it’s pretty clear that the substance of the lecture was the same as what was in Wally’s paper in global biogeochemical cycles. The idea that the Huascaran oxygen isotopes gave paleo-humidity was based on a faulty interpretation of the data, and I don’t think Wally subscribes to that idea anymore. There are indications of paleo precipitation, but that’s not the same as having a proxy for mid-tropospheric humidity — which is what affects the radiative feedback. The main reason for my inference that water vapor goes down at least as fast as the constant relative humidity assumption predicts is that it is essentially impossible to account for the observed LGM tropical cooling without an amplifying feedback of at least this magnitude. I can think of dynamical reasons the drying might be greater than Clausius-Clapeyron predicts, but they’re still in the nature of making water vapor a feedback to other drivers, not a primary driver. Things like aerosol supply could change atmospheric humidity through microphysical processes, but so far that’s just speculation, with neither paleo-observations nor theory to back it. Not impossible, and worth a look, but there’s no real support for it yet. ]

    A tipping point has been reached, and that is in the belief that rapid climate change, as proposed by Broecker, is caused by switches in the Atlantic branch of the THC. That belief is now an article of faith for everyone even with only a passing interest in climate science. This is despite the fact that Wally now believes â??the shutdown of the THC was exacerbated by a positive feedback in the form of enhanced winter sea-ice formation.â?? [Schiermeier, Nature 439 p 259] It is as difficult to roll back the idea that the THC causes abrupt climate change, as it will be to reform the Arctic sea ice once it has melted!

    In the two Simpson memoirs, as well as postulating his Paradox, he also dismissed the greenhouse effect of carbon dioxide because he considered it negligble compared with the effects of water vapour and clouds. Water vapour overlaps the CO2 bands, and clouds would limit the temperature increases. As you are probably aware it was Callendar who reintroduced the idea of CO2 being important and causing global warming. Where Simpson was obviously wrong is in the Arctic. There, there is little water vapour because of the cold, and also little cloud in the polar vortex. In that case, CO2 can dominate the greehouse effect, and cause the rapid melting of the ice we are seeing.

    [Response: Simpson wasn’t just wrong in the Arctic. CO2 bands are important even in tropical conditions, and his ideas about clouds were just not very well thought out. Entirely defensible models of tropical clouds can actually yield an amplifying effect on climate change. It’s an interesting question in history of science as to why many early 20th century climate people thought water vapor opacity would overwhelm CO2. That was not even well supported by the spectroscopy of the time. The discussion was muddied by the fact that the various ideas about how to incorporate the radiation into a prediction of surface temperature weren’t incorporated into a consistent model. That was done by Manabe and Strickler and Manabe and Wetherald in the 1960’s, which settled the issue once and for all, at least given the assumption of constant relative humidity in a warming world. ]

    BTW as far as I know Simpson’s Pradox has not been solved. Am I correct?

    [Response: Yes. It wasn’t much of a paradox. What Simpson considered a problem, Ingersoll turned to advantage in his theory of the runaway greenhouse. The crude radiation modelling of the time just didn’t allow Simpson to conclude that the OLR limitation by water vapor wasn’t a problem for Earth’s situation. It’s well-discussed towards the end of Goody and Yung –raypierre]

    Cheers, Alastair.

    Comment by Alastair McDonald — 17 Jun 2006 @ 8:04 AM

  83. Re: #79:

    So, titanium sponge ranged in 2004 from $7100 to $12,880 per ton and titanium scrap from $7600 to $8000 per ton. I wonder what it would cost to spread titanium dioxide on the Barrows airport runway?

    You don’t need much, since the coating can be extremely thin. Titanium dioxide is the primary reflective constituent of white paint. I don’t imagine it’d cost more than $10,000 retail to paint the Barrow runway (6500 ft x ~ 50ft = ~325,000ft^2) white. But…

    Over the past 30 years the annual average sea-ice extent has decreased by about 8 percent, or nearly one million square kilometers.

    Current paint tech (assuming 350 ft^2 coverage/gal and $10/gal) would cost ~$306 billion to cover that area — about what the U.S. so far has spent on the war in Iraq. (Of course you’d still need some durable floating medium to support the paint on sea areas, which would add significant costs). Still, we should be able to contrive more efficient ways to use Ti02 for this purpose, or find other materials that would be more practical.

    I am assuming that we would want to use ground-based reflectants instead of aerial ones (e.g., atmospheric dispersal of SO2) because they are far easier to control and their effects are more predictable.

    Comment by Ron — 17 Jun 2006 @ 2:27 PM

  84. Ahem. The Arctic melts, so we paint it white. And this is meant to be a serious response? Gives us climate alarmists a bad name…

    Comment by Gareth — 17 Jun 2006 @ 5:44 PM

  85. Re: #83:

    Ahem. The Arctic melts, so we paint it white. And this is meant to be a serious response? Gives us climate alarmists a bad name…

    I am not a climate alarmist, but a climate realist. We’re going to need to use all the tools at our disposal to deal with the climate change we’re causing. We’ve got to go on a carbon diet — yesterday. And we’ve also got to consider other ways to reduce the effects of excess atmospheric carbon. Increasing arctic albedo is, I suggest, one such approach.

    Refute it if you can. But mockery without data hardly helps us solve a very real problem.

    Comment by Ron — 17 Jun 2006 @ 7:23 PM

  86. Ron, what you are reading from the several responses to your initial offer at #79 is shock at the thought of what you propose without your providing an ounce of specifics that show you or others have actually begun to give that idea serious scientific and international consideration.

    You offer no glimpse at what you are suggesting. so, we can only conclude you are about spreading white paint on flat surfaces around the north Polar region.

    Perhaps you could take a moment and go past your suggestion:

    “I think geoengineering (e.g., increasing polar albedo by large-scale spraying of titanium dioxide, possibly on some kind of flotation device for the polar seas) merits research as a component of our response to climate change.” and tell us who (you perhaps) have been seriously considering such a scheme and have given due consideration to unforseen consequences such as toxic contamination of water, vegetation, species, etc.; the physical application of (what) and at what cost; and, perhaps, the shelf life of any such application of (what).

    When you provide some detail or —better– lead us to some sites and links that go into the discussion with great detail and references, then I can better understand your suggestion.

    Your comment: Refute it if you can. But mockery without data hardly helps us solve a very real problem. is correct in one sense…we have a VERY REAL PROBLEM and very little time and (even US federal money) to devise remedies and adaptation.

    I do not doubt your resolve to make a positive contribution to saving us and our children from the calamity ahead. But, YOU need to provide or lead us to the data, the research, environmental impact statements, cost-benefit analysis, etc.

    Then, we can talk.

    [Response: I like to allow wide-ranging discussion of geoengineerig proposals not because I think that any of them is likely to be a cheaper and better solution than the known and available technologies for reducing CO2 emisssions, but because they offer a playful way to think more deeply about the way the climate system operates. Ken Caldeira’s analysis of the effect of orbital mirrors is a good case in point (with regard to climate dynamics; I don’t think the mirrors are a very workable idea as technology but I won’t speak for Ken). However, it’s good to keep a bit of an idea on reality here. The idea of somehow painting the liquid ocean surface white is pretty silly. If you want to think about more constructive and practical uses of albedo engineering, the urban and suburban environment is really a much better place to start. it could have a small but useful contribution even on the global scale, but more importantly it reduces the urban heat island effect, so there’s less electricity demand for air conditioning. To keep the solar heating you’d want in the winter, you’d need to combine this with passive solar features allowing heating when you want it (heating an
    insulated black roof is not good passive solar heating!). Now here’s an important architectural question: which is better a “green roof” (living plants and moist soil) or a “white roof” (dead white panels without any moisture-holding capacity)? Is there some way to combine the benefits of both — i.e. the high albedo of the white roof with the evaporative cooling of the green roof? –raypierre]

    Comment by John L. McCormick — 18 Jun 2006 @ 8:36 AM

  87. Re: #86

    You are exactly correct that I’ve provided few specifics on deploying albedo-increasing materials, and you’re right to ask about what would be deployed, what the downsides might be, what it would cost, how it would be perceived politically, and so forth. And you are also correct that it’s my responsibility to defend any ideas I propose. But I would also point out that criticism of the form “and this is meant to be a serious response?” does not advance the debate one iota.

    That said, I am a rank amateur at understanding climate and I certainly do not have anything like a complete proposal. My point was not to present such a thing, but to diversify the debate on remediating climate change by contributing an offbeat idea that I had not heard discussed before.

    Re: raypierre comment on #86:

    Thank you for the reference to Ken Caldeira’s paper. I’ll check it out.

    Comment by Ron — 18 Jun 2006 @ 3:42 PM

  88. Re: raypierre comment on #86:

    The idea of somehow painting the liquid ocean surface white is pretty silly.

    The idea is not to dye the water, but to deploy reflective materials on some kind of strong, durable floating substrate (wild e.g., mylar).

    [Sorry about not including this in my prior comment.]

    Comment by Ron — 18 Jun 2006 @ 3:47 PM

  89. I wonder if anybody else has read Fred Pearce’s new book ‘The Last Generation’ yet. It’s a terrifying prediction of a virtual breakdown of the carbon cycle, a series of abrupt climate changes leading to massive warming – it reads very much like the scientific details behind the Revenge of Gaia (and has been praised by Lovelock), except that it makes Lovelock sound quite optimistic.

    (looking at the melting permafrost, methan hydrates, the possible Amazon die-back, tropical peat fires, oceans turning acid and killing marine life, most forests turning into carbon sources, etc).

    Comment by Almuth Ernsting — 18 Jun 2006 @ 5:19 PM

  90. RE #87: “But I would also point out that criticism of the form “and this is meant to be a serious response?” does not advance the debate one iota.”

    Sorry if you’re feeling a bit sensitive about my comment, Ron, but it does advance the debate, if only because it suggests you might like to refine not only the physical basis for your idea, but also its public presentation.

    On the other hand, painting my roof white might well be a good idea…

    Comment by Gareth — 18 Jun 2006 @ 5:40 PM

  91. RE/ #86

    Ray, you are most generous with your time and constructive, if necessarily nudging, replies to the many not-so-carefully-tuned submittals.

    Ron does open a door, however, that I also would like to see RealClimate invite more entry. How to diversify the debate on remediating climate change by contributing offbeat ideas not heard discussed before? â?¦ paraphrase Ron.

    Offbeat ideas can and should include how to expand the audience attracted to this quality discussion on the science of climate change. I would like to see more participation from individuals living in South Asia; in Nepal, India, Bangladesh, Pakistan, and Kashmir. I’d like to hear first hand accounts of the melt back of the Himalayan glaciers and the threat of overflowing glacial lakes and the affect on steam flow into the Ganges and Bramaputra Rivers.

    That region of the world is so very critical to stability of the Southern Hemisphere and, with rare coverage in at least the UK press, we in the North can only imagine what their world will become if water resources for farming and domestic use become critically imperiled.

    It would not be too difficult to encourage participation of knowledgeable people in that region if they were aware of the RealClimate web site. Perhaps the international NGO network could post a link, on their pages, to RealClimate. Perhaps I will explore this with InterAction located in Washington DC. It is an umbrella for most of the Northern humanitarian organizations such as Oxfam, Caritas, etc.

    Does anyone have suggestions how the existence of RealClimate could easily be broadcast deep into the Southern Hemisphere? Language need not be a barrier as translation software, to a degree, is easily obtained.

    Comment by John L. McCormick — 18 Jun 2006 @ 7:52 PM

  92. As someone who has benefitted greatly from raypierre’s (and other’s) comments, I also want to thank the RC scientists and contributors. Thank you. :-)

    My understanding of the purpose of this site is that it is to provide some education about climate science, especially necessary given the disinformation from various sources. Having a forum for untried ideas detracts from this purpose, and possibly also the site’s credibility.

    Comment by Brian Gordon — 19 Jun 2006 @ 1:50 PM

  93. Here´s another layperson´s perhaps offbeat idea on remediating climate change. A low-tech solution. Good work perhaps for the poor. It´s about black, not white. I already posted somewhere else but got no feedback. So,

    Carbon sequestration by producing charcoal from forests: 1) Use the pyrolysis oils for “green fuel”. 2) Leave (most of) the charcoal on site (mix it into the ground for soil enhancement a la Amazonian terra preta) and/or store it underground. 3) Let new trees grow. 4) Repeat.

    Comment by Florifulgurator — 20 Jun 2006 @ 5:39 AM

  94. Until very recently, I had done no real investigating of the global warming issue on my own, but had pretty much accepted the idea that human activity (the burning of fossil fuels and things like the destruction of the rainforsts) were most likely a driving force behind the situation. At the moment, however, due to a short but intensive period of reading, I’m no longer of that opinion. I have not yet seen Al Gore’s movie. At this point, however, I feel that his movie is not likely to give me any information that I haven’t already encountered. The “tipping point” in my mind occurred when I read a blog entry where someone said that his college professor laughed (out loud) at the idea that human beings were the cause of global warning. My first thought was to think that maybe this writer had been to college over 10 or 20 years ago. He gave the name of his professsor, however (Bill Gray), and so I looked him up assuming that more recent information probably caused the professor to change his mind. What I found, however, was a climate scientist who A) doesn’t believe that human behavior is a significant factor in global warming, and B) isn’t being paid by anyone to have that point of view. (For more information on William Gray, here are a couple of articles:

    One climate scientist alone, of course, wasn’t going to convince me. At this point, however, I feel that I can no longer accept Al Gore’s opinion that there’s a scientific consensus on the subject of global warming because obviously there isn’t. Everyone agrees that things are getting warmer, but Gore was saying that the scientific community was in agree that human activity was the central force (all one needs is a single desenting climate scientist who’s NOT being paid by some big business interest and the idea of “censensus” in my mind is bound to go out the window.)

    At this point, therefore, I guess I sort of decided that I could no longer trust what anyone is or was saying and had to start thinking and looking at the problem from the beginning (if you want anything done right, you’re going to have to do it yourself, etc. etc.) I therefore started to ask some very basic questions that most non-scientists would probably not bother to ask. Questions such as “Exactly how much air do we have on the planet?” and “How much CO2 relative to air are we putting out?” The information on this page was a bit too technical for me (I was reading through this page before I stumbled onto the opinions of Dr. Gray) so I went to Wikipedia where a simple pie charts showed me that the amount of CO2 in the atmosphere is several hundred times less than what I thought it would be (here’s the address's_atmosphere) As a non-climate scientist, I’ve been completely converted away from the idea that we human beings are causing global warming even though the political side of my being would almost rather that that argument be true. Politically, I’m much more at home with an environmentalist (as opposed to a capitalist) point of view. What really convinced me, however, were two pages I just sort of happened to stumble upon in a separate search after reading through the Wikipedia site…

    Global Warming: A Chilling Perspective

    Global Warming: A Closer Look At The Numbers

    The second page in particular (the one with the numbers) is the one that really made the most sense and led me to conclude that Dr. Gray’s position is, in the end, probably the one that’s right. I’m no climate scientist, but I’d say that I’m some who’s pretty good with your basic concepts and numbers. Would anyone care to take a stab at telling me, at this point, after reading the things I’ve shown you here, why everyone shouldn’t be laughing at the idea the human behavior is the cause of global warming? From an uneducated point of view, I was ready to accept the human cause idea hook, line and sinker. If we accept the numbers given on the second web page I provided above, however, then the TOTAL effective human contribution to the global warming greenhouse gases is so small (less than 3/10ths of 1% or 0.29%) that it makes no sense to assume that it makes any genuine difference. To suggest that human beings are causing global warming, therefore, would be like suggesting that throwing a match into a raging fire once a minute is what’s causing it to get steadily bigger and hotter.

    The earth is slowly getting warmer. Based on the pages evidence I’ve just cited, however, it’s seems very unlikely that anything we’re doing is having any real effect at all. 0.29% effectiveness, in my opinion, is very little effect. If someone told me that I was being only 0.29% effective at work, for example, I think I’d probably get fired fairly quickly after that.

    Naturally, I wouldn’t be posting here if I wasn’t hoping that someone would come back and explain exactly what (if anything) I’m missing. Am I missing something? If you believe that human behavior is driving global warming today, how would you answer the information given on the last two page (specifically the second one) that I just read? Explain to me why the human contribution to global climate forces shouldn’t be compared (as a friend of mine use to like to say) to a fart in a hurricane? Thank you. (I’m sorry if that last analogy was a bit crude, but I’ve always thought it was fairly descriptive of two things not in the same order of magnitude. Thanks again.)

    [Response: Speaking of laughing out loud, I would laugh out loud myself at the idea that Bill Gray understood even the basics of climate change physics, if it weren’t so tragic. If you want to get an inkling of just a few of the ways that Gray is confused, take a look at the post “Gray and Muddy Thinking about Global Warming.” This is a man who doesn”t even understand energy conservation, or the basic nature of the Earth’s energy budget. You ought to look at the full spectrum of evidence, try to learn what really makes climate tick, and make a decision based on sound science. And yes, Gore’s movie is a very good place to start. The science, as we said in our review of the movie, is very accurate, and quite free from exaggeration. The answer to your last question is present not just in Gore’s movie and book but in the numerous books reviewed by Gavin under “MY Review of books,” as well as spread over virtually all the articles that have appeared on RealClimate. The numbers regarding the proportion of human influence on climate forcing, on the web site you cited, are completely bogus (see Gavin’s post on the “Water Vapor Feedback,” and also the links to the illlconsidered site given in Comment #96 below). I’ll believe that your question is in earnest when I see you actually make an effort to look at the science and understand it. I’ve seen a lot of posts like this where someone pretends to be wide-eyed and having been a true green believer (like Lomborg in the old days) until they saw the light on hearing from (YOUR FAVORITE SKEPTIC HERE) and the scales fell from their eyes. Most of these starry-eyed posts are just from people whose minds are already made up. So please prove me wrong. –raypierre]

    Comment by Geoff Coe — 20 Jun 2006 @ 11:40 AM

  95. Re Ray’s response: I like to allow wide-ranging discussion of geoengineerig proposals not because I think that any of them is likely to be a cheaper and better solution than the known and available technologies for reducing CO2 emisssions, but because they offer a playful way to think more deeply about the way the climate system operates.

    I have a suggestion which I have not seen anywhere else, and might even be practical. The idea is to farm coral on flooded deserts. I would start with the Negev desert which is below sea level, so the costs of pumping sea water into it would be low.

    This idea has several advantages: First the growth of coral would remove CO2 from the atmosphere. Second, the coral, which is white, would reflect sunlight and so increase planetary albedo. Third, the flooding would be done with sea water, which would not deplete global fresh water resources, and in fact might increase them through the inevitable evaporation.

    Suitable corals which grow quickly and near the surface could be developed using genetic modification, and since the sites would be isolated from the oceans there is little danger of the new strains upsetting the natural world.

    Finacing of the projects could be achieved by issuing carbon credits for each ton of coral produced, so making it profiatble for polluting industries to finace or implement such schemes.

    Although it might seem that the pumping of sea water upto the deserts migh be expensive, in fact much of the surface of the continents is fairly low having been below sea level during the Cretaceous, in other words only a few hundred feet above present sea level. If Antarctica melts, then we may not need to pump the water as the Nullabor Desert in Australia and Arizona will be flooded anyway :-)

    Comment by Alastair McDonald — 20 Jun 2006 @ 11:51 AM

  96. #95
    Alastair, if memory serves me correctly I think you’ll find that coral is only white…when it’s dead.

    Comment by Hugh — 20 Jun 2006 @ 12:56 PM

  97. Re 94:

    Comment by Florifulgurator — 20 Jun 2006 @ 1:22 PM

  98. Geoff Coe, #94

    You should have a look in the dictionary for a definition of consensus, it does not mean unanimity. Please check here for just how strong the consensus is:

    Your clearlight web page is not reliable, the numbers it use for H2O etc greenhouse impact are, as near as I can tell, made up. Have a read here for some sourced numbers and also here for a disection of the basic implied attack on climate scientists that page delivers.

    As Ray suggests, we will see if you are as sincere as you sound, unfortunately many people make very similar presentations but then never follow through on their professed sincere interests. If you really want to get a handle on the scientific basis of this issue you can not do better than starting here:

    [Response: Indeed, I’ve been through something like this several times. The usual sequence is that, in response to what looks like a sincere request to clear up confusion, we and our readers provide a wealth of accurate material to look at. A remarkably short time later a response comes back from the original inquirer saying words to the effect that ” I’ve read all the material you’ve recommended, but I’m still not convinced.” Then, if patience hasn’t given out entirely, I usually ask, “Could you be more specific. For example, just what aspect of the water vapor vs. CO2 argument do you find unconvincing?” Usually at that point the sincere inquirer disappears entirely. Once one said to me “It’s people like me you have to convince, so don’t just tell me to read the material and think harder about it.” As I said, I would be delighted to see things take a different course in this particular instance. Hope springs eternal. –raypierre]

    Comment by Coby — 20 Jun 2006 @ 3:25 PM

  99. It’ll take hope and then some to get rid of this same bogus source. I get it handed to me every time somewhere, and then a newspaper writes a zinger and it starts all over again. Even Charlie Rose asked Gore a littany of stupid questions like these.

    Comment by Mark A. York — 20 Jun 2006 @ 3:47 PM

  100. Re 94 etc. etc. p.p.
    I recently read about blog trolls paid by “PR” firms specializing on such guerilla propaganda.
    #94 kinda sounds like one, and almost surely Ray & Mark have encountered such folks. Not worth much typing (from my European standards of discourse) – luckily there´re those great resources like realclimate or illconsidered.

    Just throw them links at the ostrich: If you get a reply, she might be seriously interested in the real world & worth some more of your precious time & brainlard.

    Comment by Florifulgurator — 20 Jun 2006 @ 6:12 PM

  101. Re #94: I do not think it is constructive to attack the motives of Geoff Coe. There is a good chance that he is sincere, but has been misled by convincing sounding information. Let me point out a few problems with the “closer look at the numbers” analysis.

    The first line in Table 1 claims 68,520 parts per billion (ppb) of carbon dioxide added to the atmosphere have a “natural” origin. No reference or justification is given. There is no possible natural source for that much carbon dioxide in that period of time. The number is totally false (four significant digits is a good clue as well), which largely invalidates the rest of the analysis which is based on that figure.

    Then in Table 3 we are told that 95% of the greenhouse effect is from water vapor. Again, no justification, just a vague reference to other skeptical web pages. This is based on the fact that about 95% of greenhouse gas by volume is indeed water vapor. It does not take into account that most of the greenhouse effect takes place in the upper atmosphere where water vapor concentrations are much lower. Understanding this takes a bit of work, which I or others here can help you with if you are really interested.

    The actual figures are about two thirds of the greenhouse effect is water vapor, the rest are from other greenhouse gases to which humans have made a significant contribution, a lot more than 0.117%.

    I understand a skeptical outlook. But maybe you should be especially skeptical about people who provide false and misleading information.

    Comment by Blair Dowden — 20 Jun 2006 @ 10:57 PM

  102. Re 96 I think your view of farming is rather naive. Their end product is dead. You can’t eat a living steer nor a living field of barley! By producing dead coral we would be locking up carbon dioxide for millions of years, just as is happening in the White Cliffs of Dover. Moreover, if it was spread over the deserts, or elsewhere, it would increase the albedo – two for the price of one!

    Comment by Alastair McDonald — 21 Jun 2006 @ 2:21 AM

  103. You guys need to either restrict this forum to a limited group of accepted members or find a way of addressing new posters without accusing them of having perverted motives. In my opinion, it really doesn’t serve your purpose. In my view, the basic cause of global warming (if human activity is the driving force) is egotism. Egotism sank the Titanic. In my opinion, egotism is really our biggest enemy here. I’d like to know if people here agree with the following newspaper article as far as the earth already being beyond the greenhouse ‘tipping point’…

    February 11, 2006 by the Guardian/UK
    A crucial global warming “tipping point” for the Earth, highlighted only last week by the British Government, has already been passed, with devastating consequences….

    Thank you.

    Comment by Geoff Coe — 21 Jun 2006 @ 5:04 AM

  104. Re #104: Geoff, I agree that the way your post by some people here was treated was unacceptable. But I did respond with respect, and you did not acknowledge or comment on that. That confirms the suspicions of the posters here – you do not really want to know. Is that correct?

    About the “common dreams” article: I am sick of this kind of hype. The facts given are accurate, but the spin is extreme. There is no “tipping point” (or non-linear effect) that I am aware of in any climate model or plausible climate scenario. Any “threshold” crossed is an arbitrary one. In this case they appear to be comparing a carbon dioxide threshold of 400 ppm, which may be about 50 years in the future, with a carbon dioxide equivalent including other greenhouse gases today. That is the same kind of dishonest accounting used by some skeptics.

    I also have a problem with implied (but not stated) relationship between agricultural yields in Africa and water shortages with global warming. There are many other human caused reasons for these problems. Again, this is dishonest.

    However, again I must point out that the basic facts are correct. Two degrees of warming in this century is a reasonable forecast. Ice cap melting is a serious issue, though more long term than they imply. The basic facts are simple: At any given global average temperature the ice caps contain a certain volume of water, in equilibrium. When it gets colder, ice caps grow and sea levels drop. When it gets warmer the ice caps shrink and sea level rises. We have data from the past on what sea levels were at various temperatures. If you plot a graph of sea level against global temperature, the slope of the line as about 6 meters per degree of warming. So two degrees of warming means 40 feet of sea level rise.

    In equilibrium. Ice does not melt instantly. Equilibrium is reached on the order of 500 to a thousand years. Major effects will be felt sooner than that. See this paper for instance. So the effects of global warming are serious, but will not be felt by the generations responsible for creating them.

    Comment by Blair Dowden — 21 Jun 2006 @ 6:43 AM

  105. Geoff, I’m not entirerly sure what you mean by egotism. Do you mean that an ecotistic and selfish discounting of the future by individuals results in unsustainable behaviors and creates collective action problems like climate change?

    As far as climate change science goes, you have two options as a lay person approaching the field.

    1) Trust the process of peer reviewed science to, in the end, arrive at the correct conclusion. At the moment, the overwhelming majority of the scientific community supports the consensus position embodied the IPCC report (see for example). While this certainly could change in the future, as new evidence emerges, given the time and effort that has gone into studying climate change at this point, the scientific consensus in itself is probably justification enough for policy makers to take the matter seriously.

    2) Read the relevent science and come to your own conclusions. While this approach is, for obvious reasons, ideally preferable over #1, it comes with its share of pitfalls. First, not every citizen in the world has the time or technical know-how to follow the thousands of relevent research publications every year that help define the field. The reason many of us laypeople trust climate scientists is that we simply don’t have the time to do as detailed a study of the current science as they do. Second, the self-discover risks mistaking cherry-picked data for the overall picture. While websites like CO2Science and their ilk seem rather convincing to the lay audience, an experienced climate scientist can easily pick it appart. Having little time to study the matter fully tends to result in people latching on to the first convincing-looking finding they stumble upon and mistaking it for the “truth”. If you are really interested in this issue, I highly recomend sticking to articles in peer-reviewed publications if possible, as they tend to be less ideologically-tinted and less prone to factual errors or hyperbole.

    Comment by Zeke Hausfather — 21 Jun 2006 @ 6:45 AM

  106. RE #104, I agree with “egotism” being a root cause of AGW. Since GW is being caused by humans, we do need to bring in the social & behavioral sciences to completely understand it, & include the psychological (motivational/cognitive), social, and cultural dimensions.

    Like why in the blank are people dragging their feet on solving this problem? They must be crazy.

    RE the topic, I just read (but have figured all along) that GW may be increasing forest fires (thru drought, early snow melt, wind increase), which would pump more GHGs into the atmosphere — another positive feedback.

    Comment by Lynn Vincentnathan — 21 Jun 2006 @ 11:14 AM

  107. Re: Geoff Coe and it’s too late

    First, my bias has been that I lean toward the “it’s probably too late” camp. This belief, quite honestly, led to some degree of depression and despair. I have kids and even a grandaughter, and I don’t feel very good about the very possible fact that…well…crap, eh?

    Anyway, this negative outlook can be self-reinforcing, because we seek out or believe things that confirm our beliefs; it takes some effort to remain open. However, the ‘doom-and-gloom’ scenario is not backed up by data. Raypierre and Hank Roberts, among others, have helped me realise this. Here’s my reasoning about it:

    1. Even if we stop emitting GHGs immediately, there are enough in the atmosphere to keep warming the earth for some time.
    2. It _appears_ that the Arctic has passed a tipping point, and will soon be ice-free in the summer.
    3. Reputable scientists believe that when the Arctic goes, the melting of the ice on Greenland is inevitable, too. (This from the paper by Hansen et al:
    4. One or both of these events could shut down or drastically slow the THC, freezing Europe.
    5. Who knows what other consequences there would be, but the social disruption might well lead to the collapse of some or all of ‘civilization,’ and therefore the deaths of millions or even billions.

    Sounds rather bleak. However, the authors of the paper referenced do NOT believe that the Arctic is necessarily lost yet, and they state that they believe much of the melting is due to non-CO2 pollution. In addition, we are entering a new era, meaning that some of what happened in the past is not necessarily indicative of what will happen in the future. Will the THC shut down? Will there be massive social disruption? Will Greenland melt? There are lots of unknowns.

    On to the article:
    The Government’s conference on Avoiding Dangerous Climate Change, held at the UK Met Office in Exeter a year ago, highlighted a clear threshold in the accumulation of greenhouse gases such as carbon dioxide (CO2) in the atmosphere, which should not be surpassed if the 2 degree point was to be avoided with “relatively high certainty”.

    This was for the concentration of CO2 and other gases such as methane and nitrous oxide, taken together in their global warming effect, to stay below 400ppm (parts per million) in CO2 terms – or in the jargon, the “equivalent concentration” of CO2 should remain below that level.

    The warning was highlighted in the official report of the Exeter conference, published last week. However, an investigation by The Independent has established that the CO2 equivalent concentration, largely unnoticed by the scientific and political communities, has now risen beyond this threshold.

    This number is not a familiar one even among climate researchers, and is not readily available.

    The 400ppm threshold is based on a paper given at Exeter by Malte Meinhausen of the Swiss Federal Institute of Technology. Dr Meinhausen reviewed a dozen studies of the probability of exceeding the 2 degrees threshold at different CO2 equivalent levels. Taken together they show that only by remaining above 400 is there a very high chance of not doing so.

    As Blair Dowden (#105) said, As Blair Dowden (#105) said,the threshold of 400 ppm is arbitrary. Nobody really knows where the tipping points are, or what each tipping point will ultimately cause. That’s the reason this threshold “is not a familiar one even among climate researchers.” Climate change skeptics use this uncertainty to argue for more study, less action, but that seems a very irresponsible course, given the likely consequences.

    [Finally, I think that “above” should be “below” in the last sentence I quoted from the article.]

    Comment by Brian Gordon — 21 Jun 2006 @ 12:40 PM

  108. Blair, the reason I didn’t respond to your post was that I didn’t see it before I posted mine (this was because I hadn’t refreshed the web page and didn’t see your posting. Sorry.)

    Zeke, naturally I agree with what you’re saying about the basic two options.

    I would like to throw another link in here for comment if I may…

    When raypierre mentioned “Lomborg” above, I went and looked him up. What is the “consensus” on this particular quote:

    Or to put it more clearly, the temperature that we would have experienced in 2094 [without the Kyoto protical] we have now postponed to 2100….In essence, the Kyoto Protocol…merely buys the world six years [and] will have surprisingly little impact.

    Thank you

    [Response: This quote is typical Lomborg — technically correct, up to a point, but giving a completely misleading impression. The assumption behind the quote is that the Kyoto Protocol is the only thing the world is going to do about global warming — that we’ll do Kyoto (if that) and then call it quits. In reality, Kyoto is just the first step in a very long process which will eventuallly involve all the world’s CO2 producers and not just the Annex I countries. Kyoto provides some impetus to develop the right technologies which can be transferred or sold to the developing world, and provides some real-world experience with the cost of CO2 abatement. It also provides the necessary moral platform for involving the developing world. If the Annex I countries can’t even commit to the modest first steps in Kyoto, they have no moral standing to demand stronger actions from poorer countries who have not benefited as much so far from industrial growth. One could quite reasonably argue whether Kyoto is the most cost-effective way to take the first step. One could not argue that the modest climate benefits accrued directly from the Kyoto reductions are justification for doing nothing at all. If anything, this is an argument for finding a way to do more, faster.

    Instead of changing the subject by tossing out yet another standard skeptics’ quote, it would be really nice if you would tell us what you think of the scientific arguments given in the mainstream literature links that various people suggested you read. –raypierre]

    Comment by Geoff Coe — 21 Jun 2006 @ 3:25 PM

  109. Raypierre, I find your reply to the Lomborg quote very depressing because, assuming that you’re right (and I’m not assuming that you’re not) the situation is impossible (or at least appears that way to me at the moment.)

    Did you know, for example, that 44% of the American population now believes that Jesus will return to earth to judge the living and the dead sometime in the next fifty years (source here and here). I mention this because these people do not see a need to deal with the “problem” of global warming. How could global warming be a problem if they’re just about to be drawn up to Heaven in the Rapture? 44%! That’s a lot! Practically half. From what I’ve gathered (see sources above), these people view any attempt to address global warming as a form of blasphemy because it is somehow an attempt to circumvent the Will of God, etc. It’s sickening, but this is part of what I meant when I said before that I see anthropogenic global warming as a function of ego (ego being the tendency to be stuck in a limited point of view.) At the same time, however, I’m not saying that we shouldn’t take action wherever we see a chance to effect a positive change. We maximize our ability to make a positive difference by having a clear picture of what we’re up against. Given that number (44%) it’s a waste of time to approach the situation with the assumption that most people are approaching the situation from the same pragmatic place that you are.

    Comment by Geoff Coe — 21 Jun 2006 @ 6:19 PM

  110. Geoff, perhaps my apologies are due (for #100)…
    Yet, I´m not sure you´re not trying to propagate some sort of “3rd-order denialism” (i.e.: “we can´t do anything because people don´t want to do anything”).

    Your 44% number is one reason why I chose to adress certain people like I did with you. This is anno domini 2006. Forget the 20th century – things will get worse this round. People who still don´t get it (AGW) are either 1) brainwashed 2) in psychopathic denial of reality 3) corrupted 4) religiously deluded or 5) I dunno. It is time to tell that straight into their face. Sorry.

    Comment by Florifulgurator — 21 Jun 2006 @ 8:17 PM

  111. Geoff,

    Some have said you were treated harshly, and it seems you have decided to agree. Myself, I concede I was curt, but I don’t think anything I said in tone or content was rude, it certainly wasn’t intended this way. Raypierre’s initial response could be seen as brusque, though I’m sure he means no offense either and, like me, is merely frustrated with a recurring pattern and the never ending citations of demonstrable junk (granted, maybe unkowingly cited).

    But you are currently failing the next test of what your real motives are. You do not respond to the offers of quality information and you abandon the subjects of your initial enquiries without conceding anything only to offer up new, and typical, septic talking points.

    Please don’t be offended if you are still sincere, this maybe your first foray into a public discussion of this issue so you don’t know the changing climate of climate change conversations, but some of us have seen a sad occurence time and time again of someone posing as a naive and sincere concerned citizen once trusting, now befuddled by conflicting scientific views only to eventually reveal that their minds were long ago firmly made up and their purpose is merely to troll and muddy the waters for everyone.

    If you are sincere, please let us know that you read and understood what we offered as references rather than continuing to offer your own. If you are not, you will soon claim we are all religious zealots who can not defend our positions logically so only attack and belittle those true denialist heros who are not afraid to cry out the emperor has no clothes.

    Who are you, Geoff Coe?

    [Response: I was brusque firstly because I had already seen enough posts worded very similarly to Geoff Coe’s to make me suspicious of the motives. I was also brusque because I find it hard to believe that, with all the valid information out there, with the well-written IPCC reports written by several hundred top scientists carefully screened for their scientific qualifications and carefully reviewed by governments and other scientists, with statements on global warming by the American Meteorological Society, American Geophysical Union, most of the world’s National Academies, with scientific research conducted by or endorsed by members of the National Academy of Sciences, MacArthur Award winners, Fellows of the Royal Society, Nobel prize winners etc. etc. — with all this out there it strains belief that anybody who was sincerely interested in seeking knowledge would light on two of the least reliable sources in the whole climate change universe and pin his beliefs on these without even doing a cursory check of what the scientific community thinks about the claims made in these sources. In light of this, I really wasn’t expecting much, but I was curious to see just how this phenomenon happens, if it is indeed a sincere request for clarification. I do appreciate that Mr. Coe didn’t just cut and run (which usually happens in these cases), but I am still awaiting enlightenment. And, I’m still awaiting any sign that Mr. Coe has read and considered the suggested material. –raypierre]

    Comment by Coby — 21 Jun 2006 @ 10:51 PM

  112. Re #104: Not to nitpick too much, but with CO2 levels currently passing through ~380ppm and growing at about 0.5%…or 2ppm…per year, we will be crossing through 400ppm of CO2 in about 10 years, not 50.

    Re #108 (Lomborg’s quote about Kyoto): Another way to look at it, in addition to what raypierre said, is simply this — Kyoto proscribes emissions for the developed (Annex I) nations for a 5-year period (2008-2012). So, even if Kyoto applied to all nations and involved producing no emissions at all for a five-year period (after which we went back to our normal ways), the net effect would only be to delay the warming effects by ~5 years! Given the numbers that Lomborg comes up with (and knowing that the actual emission cuts proscribed are not nearly so draconian), I would assume that Lomborg’s claim involves somewhat more reasonable assumptions about what happens to emissions outside of the 5 year 2008-2012 window, but this does give you the basic idea: It is silly to make statements like this about what a treaty that proscribes emissions for a 5-year time period will accomplish without at least carefully explaining your assumptions. I have seen these sort of statements made about Kyoto constantly and have yet to see any place where they are stated with the underlying assumptions carefully spelled out. Without those, the statements are, in my view, completely vacuous.

    The way I think of Kyoto is that its major purpose is to correct the current market failing by which the cost of CO2 emissions is “externalized” so that each person can use the atmosphere as a free sewer and then we collectively pay for everyone else’s emissions. Under such a system, there are no market incentives pushing the development and implementation of technologies that reduce or sequester our greenhouse gas emissions. In order for the market to have the right incentives, it is necessary to “internalize” the cost on those emissions, which is what Kyoto effectively does (especially under the emissions trading regime that has been set up).

    One of the ironies is that those who sometimes claim to be the strongest believers in markets and claim that markets will somehow solve the problem without any intervention are either ignorant about how markets actually work or are liars. They are actually hoping that magic…or at least extra-market forces such as altruism…will lead people to solve the problem because the market will not solve problems where the costs are externalized. It simply makes no sense for someone to invest money in technology to solve a problem that they are not paying for. (Of course, we are all collectively paying for our emissions through global warming and other environmental problems, but nearly all of the costs each of us bears is due to the emissions of everyone else. Only a vanishingly small amount is due to our own emissions.)

    Comment by Joel Shore — 21 Jun 2006 @ 11:15 PM

  113. Coby wrote: “Who are you, Geoff Coe?”
    I wrote a reply to this but then felt uncomfortable about posting stuff about myself up here. For those who want to read what I wrote, click here. I understand the fear of having one’s time wasted by someone who, in the end, may not be sincere and may have already formed an undisclosed opinion, but I really don’t know what I can do at this point to address that fear. I think that everyone must naturally make up his or her own mind. Besides what I wrote on the other page, I’m sort of at a loss to know what would be the right or proper answer.

    Comment by Geoff Coe — 22 Jun 2006 @ 3:58 AM

  114. Re #112: Joel, of course you are correct about carbon dioxide levels. I guess the Common Dreams article threw so many arbitrary numbers around that I got confused myself. Setting 400 ppm as a magic barrier when we are almost already there makes no sense.

    I think the only way to rational market decisions about fossil fuel use is to place a carbon tax on them at the source, although I realize there are problems on how to handle the revenue. I am not sure how this fits in with the Kyoto emissions trading scheme.

    Re #113: Geoff, I believed you from the start. My only suggestion is to follow through on your questions before changing the topic.

    Comment by Blair Dowden — 22 Jun 2006 @ 6:46 AM

  115. Hi Geoff,

    To address that fear, just let me know if you understand the deceit in the clearlight pages when it comes to H2O vs CO2 in climate change. Specifically, did you read and do you follow the arguments and information in these three links?

    Are you reassured that, Bill Gray’s contemptuous laughter aside, there is in fact a very strong scientific consensus that GW is real and CO2 emissions are the primary driver?
    (Bill Gray is in a *very* small majority even in the sceptic world by denying the above)

    And have you had time to look into this document?

    A sincere interest can not be better served than by reading at least the Summary for Policy Makers in the above IPCC report, and hopefully you would have time to read summaries and introductions of the various chapters as well.

    Best wishes,

    Comment by Coby — 22 Jun 2006 @ 10:57 AM

  116. (Bill Gray is in a *very* small majority even in the sceptic world by denying the above)

    should have been “small minority” of course…

    Comment by Coby — 22 Jun 2006 @ 1:59 PM

  117. Coby: I am reading/looking at the pages that you posted. In general, I want people to understand that, looking back at my first post (#94), I can understand now why people here would think that I might not be entering the situation with a fully open mind. Chalk it up to being unaware of the negative experiences that people on this list have been through. Please be clear that my central interest here is the World Peace Society Project and learning that will assist me in moving that project forward. Given the extreme gravity of the global warming issue, it’s clearly important that I be informed about it. From a conventional point of view, however, I think that my approach to learning is bound to look a bit chaotic or scattered at times. You should know, however, that every link or reference given to me by people from this site has either been bookmarked or recorded. I wouldn’t want anyone here to feel that their efforts with me were wasted. World peace does boil down to trust and I am satisfied that the thinkers on this page are both diligent and sincere. At this point, therefore, I don’t understand all the science. In my opinion, however, if there’s a large group of diligent and thoughtful individuals who believe that global warming is being driven by human CO2 emissions, then the proper and moral thing to do is to assume that’s the truth until it’s been thoroughly disproven. To do anything else is playing Russian Roulette with the world. So please don’t get angry at me if I don’t end up grasping all the intricacies of climate science. I am interested. How much I’ll learn and when, however, will depend on a number of different factors. I’d like to suggest, however, that even when you’re speaking with someone who isn’t sincere, you’re sincere efforts always make a difference, even if it’s not the particular difference that you had in mind. That’s my suggestion.

    Comment by Geoff Coe — 22 Jun 2006 @ 3:59 PM

  118. Mr. Coe,

    You have much to read and I do hope you take some time off, some serious time off to self-educate just like many of us non-scientists have had to do. Then, maybe this thread can move on.

    Your comment below says volumes about the depth to which you seem to be plowing into the many informative and scientific sites provided by thoughtful individuals with the sincere hope you will read them; i.e., the IPCC Third Review to name just one.

    “In my opinion, however, if there’s a large group of diligent and thoughtful individuals who believe that global warming is being driven by human CO2 emissions, then the proper and moral thing to do is to assume that’s the truth until it’s been thoroughly disproven.”

    The train is way down the track and it aint slowing down.

    Comment by John L. McCormick — 22 Jun 2006 @ 9:28 PM

  119. In my opinion, however, if there’s a large group of diligent and thoughtful individuals who believe that global warming is being driven by human CO2 emissions, then the proper and moral thing to do is to assume that’s the truth until it’s been thoroughly disproven.

    Nicely put and I heartily agree. It is refreshing to hear someone in the early learning phase, such as yourself, understand that, rather than take the opposite view: until we hear the hull buckling on the rocks, full speed ahead – which is what the “prove it beyond a doubt first” attitude boils to.

    Comment by Coby — 22 Jun 2006 @ 10:19 PM

  120. To return to the original topic, the June 16 issue of Science contains the article Permafrost and the Global Carbon Budget, which claims that previous estimates of carbon in Arctic permafrost are too low. They suggest that 500 gigatonnes (Gt) carbon are tied up in “yedoma” (frozen loess) and another 400 Gt in other permafrost (compared to 730 Gt in the air today). After it melts, they say most of the carbon is released within a century. In what they call the “extreme scenario” where all the tundra melts during this century, carbon dioxide levels could double from this source alone.

    I would like to know how different this information is than what is currently believed, and level of uncertainty you think there is.

    [Response:I had seen comparable numbers to this for carbon inventories in Arctic permafrost, but this is a more reliable-looking (more detailed) treatment than I’d seen before (an old paper by MacDonald who pulls a number out of the air, is the paper everyone seems to cite). I have to say that the second-to-last paragraph in the paper, about carbon isotopes and reservoir changes during glacial time, seems a bit garbled to me. The sizable marine organic carbon reservoir is dissolved organic matter, which is today thousands of years old (by radiocarbon). It’s not clear what determines the size of this reservoir, nor is it clear from the text that this is what the authors are referring to anyway. But for the future, the prediction that melting soils would release carbon, relatively quickly, and potentially a lot of it, that conclusion seems robust to me. David]

    Comment by Blair Dowden — 25 Jun 2006 @ 5:07 PM

  121. Thank you, David. If I understand you correctly, this paper confirms our present understanding, rather than revising the impact of melting permafrost upward. The paper does not give a ratio of methane to carbon dioxide for emissons from melting permafrost, but I assume the methane portion is significant. Since melting of permafrost has already begun, one would expect it to affect methane concentration. But methane levels seem to have levelled off, at least for the past few years. The missing piece of information is how much permafrost has melted, and what portion of its carbon has been released.

    Comment by Blair Dowden — 26 Jun 2006 @ 7:26 AM

  122. […] much CO2 really is in the air and how much is actually going up into the atmosphere?  Right now, the ocean is taking up 2/7 of our carbon emissions and is helping regulate the amount that is being…  Our atmosphere and world are trying to regulate the temperatures but may no longer be able to […]

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